2006 Mercury Grand Marquis Info Systems & Data Sheets
The 2006 Mercury Grand Marquis shares the Panther platform with the Crown Victoria and Town Car — same 4.6L SOHC 2-valve Romeo V8, same 4R75W 4-speed automatic, same ETC drive-by-wire system, same three-connector 150-pin PCM harness. What distinguishes the 2006 Grand Marquis at the junction box level are a handful of specific changes from the 2005 model. The most significant: BJB fuse #1 steps from 20A to 25A and adds hazard circuit coverage. BJB fuse #16 changes from the DRL module at 20A to fog lamps at 15A — 2006 was the first Grand Marquis year with factory fog lamps, and relay position #205 is now populated as the fog lamp relay where it sat empty on the 2005. The PCM connector data changes substantially from 2005 to 2006 on both C175T and C175B. On C175T, several 2005-specific indicator control lines go away — check fuel cap, cruise set indicator, engine vacuum signal, check engine indicator, overdrive indicator, cylinder head temp indicator, SCP bus lines, fuel gauge sender, and generator/battery indicator are all dropped for 2006. C175B drops the brake pedal position switch at pin 8, the A/C evaporator temperature sensor at pin 15, traction control indicator at pin 33, traction assist indicator at pin 37, and fuel level data at pin 38. Pin 48 on C175T also corrects from #12 heater to #22 heater — an error present in several 2005-based diagrams that gets carried forward if not caught. If you're working a 2006 Grand Marquis with a 2005 diagram, the PCM pins above are where you'll get mismatches.
Download Your Schematics:
- 2006 Mercury Grand Marquis Battery Junction Fuse Box Schematic Data Sheet
- 2006 Mercury Grand Marquis Powertrain Control Module Schematic Data Sheet
- 2006 Mercury Grand Marquis Central Junction Box Schematic Data Sheet
Resources:
- Ford OBD-2 Diagnostic Trouble Codes List
- 2003–2011 Panther Platform Resources & Manuals List
- Label Installation Guide
Labels:
In this post:
- Engine Specifications
- Transmission Specifications
- Battery Junction Box Fuse Panel Data & Info
- Powertrain Control Module Data & Info
- Central Junction Fuse Box Data & Info
- Known Issues & TSB Reference
- Scheduled Maintenance Intervals
Engine Specifications
The 2006 Grand Marquis uses the same 4.6L Romeo-cast SOHC V8 as the Crown Victoria and Town Car. Power output is 224 hp on the standard GS and LS trims. The Grand Marquis does not have a performance-package equivalent to the Crown Vic P71 — there is no factory intake or calibration upgrade from Mercury for this model year on the Grand Marquis. The 2006 PCM calibration is specific to the Grand Marquis and is not shared with either the Crown Victoria or Town Car. It requires VIN programming after replacement. All figures below are SAE net.
| Specification | Value |
|---|---|
| Engine Family | Ford Modular V8 — Romeo cast |
| Displacement | 4.6L (4,601 cc / 280.8 cu in) |
| Configuration | V8, 90° — SOHC, 2 valves per cylinder (16 total) |
| Bore × Stroke | 90.2 mm × 90.0 mm (3.55 in × 3.54 in) |
| Compression Ratio | 9.4:1 |
| Horsepower | 224 hp @ 4,800 rpm (SAE net) |
| Torque | 272 lb-ft @ 4,000 rpm (SAE net) |
| Redline | ~5,550 rpm |
| Fuel Type | Unleaded — 87 octane minimum (regular) |
| Fuel Injection | Sequential Multi-Port Fuel Injection (SEFI) |
| Throttle Control | Electronic (Drive-By-Wire / ETC) |
| Ignition | Coil-on-plug (COP) — 8 individual coils, no distributor |
| Engine Oil Capacity | 6 quarts with filter change |
| Engine Oil Spec | SAE 5W-20 (Motorcraft) |
| Coolant Capacity | ~17.9 liters (18.9 qts / 4.7 gal) |
| Coolant Spec | Motorcraft Premium Gold (yellow) — do not mix with green |
| Fuel Tank Capacity | 19 gallons (gasoline) |
Transmission Specifications
The 2006 Grand Marquis uses the 4R75W, same as the Crown Victoria and Town Car from 2005 onward. The 4R75W replaced the 4R70W starting in 2005 across the Panther platform — gear ratios and fluid spec are identical on all three models. The same 2005–2006 TCC-in-2nd TSB applies here: premature torque converter clutch lockup causing a hesitation or stumble at light throttle in the 15–30 mph range, fixed by a PCM reflash. Fluid spec is Mercon V only — standard Mercon and Dexron both degrade friction material in this unit. Do not substitute.
| Specification | Value |
|---|---|
| Transmission Model | Ford 4R75W 4-speed automatic |
| Type | Rear-wheel drive, 4-speed automatic with overdrive |
| 1st Gear Ratio | 2.84:1 |
| 2nd Gear Ratio | 1.55:1 |
| 3rd Gear Ratio | 1.00:1 |
| 4th Gear Ratio (OD) | 0.70:1 |
| Reverse Ratio | 2.32:1 |
| Turbine Speed Sensor | Yes — TSS (C175T pin 15) feeds PCM for TC slip monitoring |
| Fluid Type | Mercon V ATF — do not substitute Mercon or Dexron |
| Fluid Capacity | ~13.9 quarts (total system, dry fill) |
| Rear Axle | Ford 8.8 inch — Traction-Lok (limited slip) optional |
| Axle Ratio Options | 2.73:1 (standard) / 3.27:1 (LS Ultimate) |
| Rear Axle Fluid | 75W-140 synthetic (Traction-Lok) or 80W-90 (standard) |
| Rear Axle Fluid Note | Add 4 oz. Motorcraft XL-3 friction modifier for Traction-Lok |
Battery Junction Box Fuse Panel Data & Info
Location: Engine bay, passenger side, behind battery | All information verified with AllData.
The Grand Marquis BJB layout is nearly identical to the Crown Victoria for 2006, with two model-specific differences worth knowing. First, position #16 is a fog lamp fuse at 15A — 2006 was the first Grand Marquis year with factory-installed fog lamps, so if you're working a 2005 and looking for where the fogs are wired, they're not. They weren't there yet. The fog lamp relay at position #205 is populated for 2006 but was empty on the 2005 Grand Marquis. Second, position #5 feeds the RASM and VAPS module — the Grand Marquis LS Ultimate had the same rear air suspension as the Town Car, fed here. On standard GS and LS trims without air suspension, this fuse still feeds the VAPS (variable assist power steering) module; it's not empty on non-air-suspension cars. The rest of the BJB layout mirrors the 2006 Crown Victoria civilian configuration: fuse #1 at 25A with hazard coverage, fuse #21 adding the A/C clutch relay coil to powertrain loads, and fuse #24 (radio mute) still present on the Grand Marquis where it was dropped on the 2006 Crown Vic. The same moisture-and-heat failure path applies here — water in through a missing or damaged cover causes corrosion, resistance, heat, and cascading failures. Voltage-drop test the main feeds and grounds after any BJB repair; anything above 0.1–0.2V means the resistance is still in the circuit.
Both maxi-fuse feeds to the CJB — positions #103 (50A) and #104 (40A) — are the first thing to check when multiple interior fuse circuits go dark at once without any obvious blown CJB fuse. A failed maxi-fuse under the hood will kill the entire branch it feeds without showing any sign of trouble at the dash panel.
| # | AMP | FUNCTION |
|---|---|---|
| 1 | 25A | Ignition switch (Key in, RUN 1, RUN 2), Hazards |
| 2 | 25A | Ignition switch (RUN/START, RUN/ACC, START) |
| 3 | 10A | Powertrain Control Module (PCM) keep alive power |
| 4 | 20A | Fuel relay feed |
| 5 | 10A | Rear Air Suspension Module (RASM), VAPS module |
| 6 | 15A | Alternator regulator |
| 7 | 30A | PCM relay feed |
| 8 | 20A | Driver's Door Module (DDM), Door locks |
| 9 | 15A | Ignition coil relay feed |
| 10 | 20A | Horn relay feed |
| 11 | 15A | A/C clutch relay feed |
| 12 | 25A | Audio |
| 13 | 20A | Instrument panel power point |
| 14 | 20A | Stop lamp switch |
| 15 | 20A | Heated seats |
| 16 | 15A | Fog lamps (2006 addition — not present on 2005) |
| 17 | — | Not used |
| 18 | — | Not used |
| 19 | 15A | Powertrain Control Module (PCM), Fuel injectors |
| 20 | 15A | Mass Air Flow (MAF) sensor, IAT sensor |
| 21 | 15A | Powertrain loads and sensors, A/C clutch relay coil |
| 22 | — | Not used |
| 23 | — | Not used |
| 24 | 5A | Radio mute |
| 101 | 40A | Blower relay feed |
| 102 | 50A | Cooling fan |
| 103 | 50A | Instrument panel (I/P) fuse box feed #1 — I/P fuses 23, 25, 27, and 31 |
| 104 | 40A | Instrument panel (I/P) fuse box feed #2 — I/P fuses 1, 3, 5, 7, and 9 |
| 105 | 30A | Starter relay feed |
| 106 | 40A | Anti-lock Brake System (ABS) module (pump) |
| 107 | 40A | Rear defroster relay feed |
| 108 | 20A | Moonroof |
| 109 | 20A | ABS module (valves) |
| 110 | 30A | Wiper module |
| 111 | — | Not used |
| 112 | 30A | Air suspension compressor (LS Ultimate only) |
| 113 | — | Not used |
| 114 | — | Not used |
| 115 | — | Not used |
| 116 | — | Not used |
| 117 | — | Not used |
| 118 | — | Not used |
| 201 | 1/2 ISO | A/C clutch relay |
| 202 | — | Not used |
| 203 | 1/2 ISO | Ignition coil relay |
| 204 | 1/2 ISO | PCM relay |
| 205 | 1/2 ISO | Fog lamps relay (2006 addition — not used on 2005) |
| 206 | 1/2 ISO | Fuel relay |
| 207 | — | Not used |
| 208 | — | Not used |
| 209 | 1/2 ISO | Horn relay |
| 301 | Full ISO | Starter relay |
| 302 | Full ISO | Air compressor relay (air suspension) |
| 303 | Full ISO | Blower relay |
| 304 | Full ISO | Power windows (RUN/ACC) |
| 401 | — | Not used |
| 501 | Diode | A/C clutch |
| 502 | Diode | PCM |
| 503 | Diode | Horn, Door latch |
| 601 | 20A Circuit Breaker | Power seats, Lumbar, Deck-lid |
| 602 | 20A Circuit Breaker | Power windows relay feed (RUN/ACC) |
Legend
- # — Terminal Position
- ABS — Anti-lock Brake System
- ACC — Accessory
- AMP — Terminal Amperage
- DDM — Driver's Door Module
- EATC — Electronic Automatic Temperature Control
- FUNCTION — Circuit Function
- I/P — Instrument Panel
- ISO — International Standards Organization
- LCM — Lighting Control Module
- PCM — Powertrain Control Module
- RASM — Rear Air Suspension Module
- VAPS — Variable Assist Power Steering
Powertrain Control Module (PCM/ECU) Data & Info
Location: Engine bay, driver's side inner fender | All information verified with AllData.
The 2006 Grand Marquis PCM sits on the driver's side inner fender and manages the ETC drive-by-wire system through the same three-connector 150-pin harness used across the 2006 Panther platform: C175T (left), C175B (center), C175E (right). The ETC setup is the same as the 2006 Crown Victoria — three APP sensors at C175B providing redundant pedal-position signals, two TPS sensors at C175E confirming throttle plate angle, and the PCM driving the throttle motor directly through C175E pins 47 and 48. Any two-sensor disagreement outside calibrated tolerance sets an ETC fault, illuminates the wrench light, and may reduce or restrict throttle. What changed significantly from 2005 to 2006 is the C175T connector. A large number of 2005-specific SCP bus indicator and signal lines are removed: check fuel cap indicator (pin 12), cruise set indicator (pin 13), engine vacuum signal (pin 21), check engine indicator (pin 22), fuel gauge sender (pin 30), overdrive indicator (pin 31), cylinder head temp indicator (pin 32), SCP bus+ (pin 35), SCP bus− (pin 36), and generator/battery indicator (pin 39) are all not used on the 2006. Those functions either migrated to other modules or were eliminated. Also note: C175T pin 48 is the HO2S #22 heater on the 2006 — it was incorrectly shown as #12 heater on some 2005-derived diagrams, so confirm which heater circuit you're looking at before probing.
C175B also drops several 2005-specific circuits. Pin 8 (brake pedal position switch switched power) is not used on the 2006. Pin 15 (A/C evaporator discharge air temperature sensor) is not used. Pins 29 (ABS lamp), 33 (traction control indicator), 37 (traction assist indicator), and 38 (fuel level data) are all not used — those signals moved to other modules between model years. Pin 40 changes from a fuel tank pressure transducer signal on 2005 to a reference voltage line (BR/WH, circuit 351) on 2006. C175E is largely the same as 2005 with the addition of the heated PCV control at pin 26 (WH/OG, circuit 369). Ground integrity at C175B pins 47–50 (BK/WH, circuit 570, 18 gauge) is still the first diagnostic check on any PCM communication fault, transmission shift complaint, or intermittent misfire code.
Three failure patterns to rule out on a high-mileage 2006 Grand Marquis before condemning the PCM: (1) ground cluster corrosion at C175B pins 47–50 — voltage drop above 0.1V under load points to a ground problem; (2) ETC faults (P2100–P2119, wrench light) — clean the throttle bore and plate before replacing anything, carbon buildup causes enough binding to trigger false throttle position faults; (3) COP boot failures — cracked boots allow voltage spikes to backfeed through C175E into PCM output drivers, and sustained misfires (P030X) without a boot inspection aren't a complete diagnosis. The 2006 PCM requires VIN programming after replacement and is not shared with the Crown Victoria or Town Car calibration.
C175T (BK) | LEFT (12B637)
| PIN | COLOR | CIRCUIT | GAUGE | FUNCTION |
|---|---|---|---|---|
| 1 | — | — | — | Not used |
| 2 | — | — | — | Not used |
| 3 | DB/YE | 136 | 20 | Output shaft speed (OSS) sensor signal |
| 4 | — | — | — | Not used |
| 5 | — | — | — | Not used |
| 6 | — | — | — | Not used |
| 7 | — | — | — | Not used |
| 8 | — | — | — | Not used |
| 9 | — | — | — | Not used |
| 10 | — | — | — | Not used |
| 11 | WH/YE | 925 | 20 | Electronic Pressure Control (EPC) solenoid |
| 12 | — | — | — | Not used |
| 13 | — | — | — | Not used |
| 14 | — | — | — | Not used |
| 15 | DG/WH | 970 | 20 | Turbine shaft speed (TSS) sensor signal |
| 16 | YE/BK | 1144 | 20 | Digital Transmission Range (DTR) sensor — TR1 |
| 17 | LB/BK | 1145 | 20 | Digital Transmission Range (DTR) sensor — TR2 |
| 18 | — | — | — | Not used |
| 19 | YE/LB | 1816 | 20 | Generator communication |
| 20 | — | — | — | Not used |
| 21 | — | — | — | Not used |
| 22 | — | — | — | Not used |
| 23 | — | — | — | Not used |
| 24 | RD/LG | 392 | 18 | Heated oxygen sensor (HO2S) #12 input |
| 25 | VT/LG | 393 | 18 | Heated oxygen sensor (HO2S) #22 input |
| 26 | — | — | — | Not used |
| 27 | RD/BK | 1268 | 20 | Digital Transmission Range (DTR) sensor — TR3A |
| 28 | WH/BK | 1143 | 20 | Digital Transmission Range (DTR) sensor — TR4 |
| 29 | OG/BK | 923 | 20 | Transmission Fluid Temperature (TFT) sensor |
| 30 | — | — | — | Not used |
| 31 | — | — | — | Not used |
| 32 | — | — | — | Not used |
| 33 | OG/RD | 1269 | 20 | Anti-theft indicator control |
| 34 | — | — | — | Not used |
| 35 | — | — | — | Not used |
| 36 | — | — | — | Not used |
| 37 | GY/BK | 679 | 20 | Vehicle speed signal |
| 38 | YE | 1817 | 20 | Generator monitor circuit |
| 39 | — | — | — | Not used |
| 40 | — | — | — | Not used |
| 41 | GY/RD | 359 | 20 | Signal return |
| 42 | OG/YE | 237 | 20 | Shift solenoid A |
| 43 | VT/OG | 315 | 20 | Shift solenoid B |
| 44 | — | — | — | Not used |
| 45 | — | — | — | Not used |
| 46 | VT/YE | 126 | 20 | Torque Converter Clutch (TCC) solenoid |
| 47 | WH/BK | 389 | 18 | Heated oxygen sensor (HO2S) #12 heater |
| 48 | TN/YE | 390 | 18 | Heated oxygen sensor (HO2S) #22 heater |
| 49 | — | — | — | Not used |
| 50 | — | — | — | Not used |
C175B (BK) | CENTER (14290)
| PIN | COLOR | CIRCUIT | GAUGE | FUNCTION |
|---|---|---|---|---|
| 1 | — | — | — | Not used |
| 2 | BK | 3405 | 20 | Starter relay control |
| 3 | PK/LB | 883 | 20 | Low charge protection switch signal |
| 4 | WH/LB | 3093 | 20 | Electronic Throttle Control (ETC), VREF 1 |
| 5 | TN/YE | 1283 | 20 | Accelerator pedal position (APP) sensor 1 signal |
| 6 | TN/WH | 1284 | 20 | Electronic Throttle Control (ETC), signal return |
| 7 | OG | 636 | 20 | Deactivator switch — switched power |
| 8 | — | — | — | Not used |
| 9 | RD/PK | 791 | 20 | Fuel tank pressure transducer sensor reference voltage |
| 10 | BK | 57 | 18 | Ground |
| 11 | WH/LG | 1827 | 20 | CAN bus+ |
| 12 | LB/OG | 926 | 20 | Modulated fuel pump signal |
| 13 | VT/WH | 91 | 20 | Evaporative emission (EVAP) canister vent valve control |
| 14 | — | — | — | Not used |
| 15 | — | — | — | Not used |
| 16 | — | — | — | Not used |
| 17 | WH | 3012 | 20 | Accelerator pedal position (APP) sensor 2 signal |
| 18 | — | — | — | Not used |
| 19 | LB/BK | 151 | 20 | Speed control switch reference voltage |
| 20 | YE/BK | 1799 | 20 | RDI / VEMS signal |
| 21 | DG/YE | 238 | 20 | Fuel pump monitor |
| 22 | WH/LG | 1215 | 20 | TX signal |
| 23 | PK/LG | 1828 | 20 | CAN bus− |
| 24 | LB/BK | 3091 | 20 | Electronic Throttle Control (ETC), VREF 2 |
| 25 | OG/LB | 73 | 20 | A/C clutch relay control |
| 26 | GY | 743 | 20 | Intake air temperature (IAT) sensor signal |
| 27 | TN/WH | 224 | 20 | Transmission control switch signal |
| 28 | WH/RD | 3015 | 20 | Accelerator pedal position (APP) sensor 3 signal |
| 29 | — | — | — | Not used |
| 30 | DG/OG | 848 | 20 | Speed control switch — signal return |
| 31 | WH/BK | 1154 | 20 | A/C pressure transducer sensor signal |
| 32 | LB/RD | 967 | 20 | Mass Air Flow (MAF) sensor signal |
| 33 | — | — | — | Not used |
| 34 | LG/BK | 191 | 20 | Vapor Management Valve (VMV) control |
| 35 | RD | 361 | 20 | Voltage supplied in start and run (overload protected) |
| 36 | RD | 361 | 20 | Voltage supplied in start and run (overload protected) |
| 37 | — | — | — | Not used |
| 38 | — | — | — | Not used |
| 39 | — | — | — | Not used |
| 40 | BR/WH | 351 | 20 | Reference voltage |
| 41 | GY/RD | 359 | 20 | Signal return |
| 42 | GY/OG | 1216 | 20 | RX signal |
| 43 | TN/LB | 968 | 20 | Mass Air Flow (MAF) sensor signal return |
| 44 | VT | 107 | 20 | Flash / EEPROM power supply |
| 45 | RD/WH | 729 | 20 | Voltage supplied at all times (overload protected) |
| 46 | YE/LG | 330 | 20 | Power steering pressure switch signal |
| 47 | BK/WH | 570 | 18 | Ground |
| 48 | BK/WH | 570 | 18 | Ground |
| 49 | BK/WH | 570 | 18 | Ground |
| 50 | BK/WH | 570 | 18 | Ground |
C175E (BK) | RIGHT (12B637)
| PIN | COLOR | CIRCUIT | GAUGE | FUNCTION |
|---|---|---|---|---|
| 1 | LG/WH | 1024 | 20 | Coil-on-plug (COP) 1 control |
| 2 | TN | 555 | 20 | Fuel injector 1 control |
| 3 | WH | 556 | 20 | Fuel injector 2 control |
| 4 | BR/YE | 557 | 20 | Fuel injector 3 control |
| 5 | BR/LB | 558 | 20 | Fuel injector 4 control |
| 6 | BR/PK | 360 | 20 | Signal return |
| 7 | PK/OG | 1858 | 20 | Electronic Throttle Control (ETC) module signal return |
| 8 | TN/BK | 559 | 20 | Fuel injector 5 control |
| 9 | LG/OG | 560 | 20 | Fuel injector 6 control |
| 10 | TN/RD | 561 | 20 | Fuel injector 7 control |
| 11 | LB | 562 | 20 | Fuel injector 8 control |
| 12 | PK/WH | 1026 | 20 | Coil-on-plug (COP) 2 control |
| 13 | — | — | — | Not used |
| 14 | RD/OG | 229 | 20 | Engine cooling fan module control |
| 15 | — | — | — | Not used |
| 16 | — | — | — | Not used |
| 17 | — | — | — | Not used |
| 18 | YE/WH | 1857 | 20 | Electronic Throttle Control (ETC) module reference voltage |
| 19 | GY/WH | 355 | 20 | Throttle Position Sensor (TPS) signal 1 |
| 20 | YE | 1273 | 20 | Knock sensor − |
| 21 | — | — | — | Not used |
| 22 | — | — | — | Not used |
| 23 | LB/RD | 3067 | 20 | Manifold Absolute Pressure (MAP) sensor input |
| 24 | WH/PK | 1028 | 20 | Coil-on-plug (COP) 3 control |
| 25 | DB/OG | 282 | 20 | Camshaft position sensor signal |
| 26 | WH/OG | 369 | 20 | Heated PCV control |
| 27 | — | — | — | Not used |
| 28 | — | — | — | Not used |
| 29 | YE/WH | 357 | 20 | Throttle Position Sensor (TPS) signal 2 |
| 30 | GY/LB | 74 | 18 | Heated oxygen sensor (HO2S) #11 input |
| 31 | RD/BK | 94 | 18 | Heated oxygen sensor (HO2S) #21 input |
| 32 | YE/RD | 310 | 20 | Knock sensor + |
| 33 | YE/LG | 1102 | 20 | Cylinder head temperature sensor signal |
| 34 | BK/PK | 138 | 20 | Crankshaft position sensor + |
| 35 | DG/VT | 1030 | 20 | Coil-on-plug (COP) 4 control |
| 36 | LB | 1164 | 20 | Injector temperature sensor signal |
| 37 | RD/PK | 141 | 20 | Injector pressure sensor signal |
| 38 | LG/YE | 1021 | 20 | Coil-on-plug (COP) 5 control |
| 39 | OG/YE | 1025 | 20 | Coil-on-plug (COP) 6 control |
| 40 | BR/WH | 351 | 20 | Reference voltage |
| 41 | GY/RD | 359 | 20 | Signal return |
| 42 | PK/LB | 1027 | 20 | Coil-on-plug (COP) 7 control |
| 43 | WH/RD | 1029 | 20 | Coil-on-plug (COP) 8 control |
| 44 | BR/LG | 352 | 20 | Differential Pressure Feedback EGR (DPFE) sensor input |
| 45 | GY/YE | 139 | 20 | Crankshaft position sensor − |
| 46 | — | — | — | Not used |
| 47 | DB/YE | 1835 | 18 | Electronic Throttle Control (ETC) motor +/− |
| 48 | OG/YE | 1836 | 18 | Electronic Throttle Control (ETC) motor +/− |
| 49 | RD/WH | 387 | 18 | Heated oxygen sensor (HO2S) #11 heater |
| 50 | YE/LB | 388 | 18 | Heated oxygen sensor (HO2S) #21 heater |
Wire Color Legend
- BK — Black
- BR — Brown
- DB — Dark Blue
- DG — Dark Green
- GY — Gray
- LB — Light Blue
- LG — Light Green
- OG — Orange
- PK — Pink
- RD — Red
- TN — Tan
- VT — Violet
- WH — White
- YE — Yellow
Central Junction Fuse Box Data & Info
Location: Driver's side compartment, under steering wheel | All information verified with AllData.
The Grand Marquis CJB layout is shared with the Crown Victoria at most positions but differs in a few key areas that reflect the Mercury's trim content. Position #7 changes from 2005 to 2006: the 2005 used it for LCM, park lamps, and switch illumination at 10A, while the 2006 routes it to corner lamps at 15A — a direct result of the 2006 lighting system changes that came with the fog lamp and cornering lamp additions. Position #9 flips as well: the 2005 routed LCM headlamp and cornering lamp circuits there, while the 2006 uses it for switch illumination only. Position #4 combines ABS module with RASM and VAPS on 2006 (was ABS + PCV heater on 2005). Position #26 differs between years — on 2005 it fed the analog cluster, warning lamp module, LCM, overdrive cancel switch, and rear defroster relay coil; on 2006 it feeds cluster, LCM, overdrive cancel switch, and rear defroster relay coil with the analog cluster and warning lamp module moving elsewhere. The fire suppression module at position #33 may be populated on Grand Marquis units that served in taxi or livery fleets — it's not exclusive to police vehicles on this platform. Always check the BJB positions #103 and #104 first before chasing CJB failures on a wide-area electrical complaint. A dead maxi-fuse upstream kills the entire downstream branch without showing any obvious blown fuse at the CJB.
Water intrusion through the cowl or firewall grommets reaching the driver's footwell and CJB area is the same failure mode as on every other Panther. The fix is always two steps in order: seal the water source first, then inspect and repair or replace corroded CJB terminals. Cleaning oxidized contacts without eliminating the moisture path means the corrosion returns on the same timeline.
| # | AMP | FUNCTION |
|---|---|---|
| 1 | 15A | Lighting Control Module (LCM), Instrument cluster, Taxi roof lamp switch, Door ajar indicator |
| 2 | 10A | Function selector switch assembly (19B888), Electronic Automatic Temperature Control (EATC) module (19980), Blower motor relay |
| 3 | 10A | Radio (18806), Electronic Automatic Temperature Control (EATC) module (19980) |
| 4 | 10A | ABS control module, Rear Air Suspension Module (RASM), Variable Assist Power Steering (VAPS) |
| 5 | 10A | Brake shift interlock (3Z719), Deactivator switch, Brake pedal position switch (13480) |
| 6 | 10A | Instrument cluster |
| 7 | 15A | Corner lamps |
| 8 | 10A | Variable Assist Power Steering (VAPS) module, Air suspension module (3C142) |
| 9 | 10A | Switch illumination |
| 10 | 5A | Audio mute (START) |
| 11 | 10A | Window relay coil (ON/ACC) |
| 12 | 10A | Starter relay coil (START), Digital Transmission Range (DTR) sensor |
| 13 | 10A | Windshield wiper motor (17508) |
| 14 | 10A | Brake shift interlock (3Z719) |
| 15 | 7.5A | Lighting Control Module (LCM), Seat heater switch driver side, Door lock switch driver side (14028), Door lock switch passenger side (14028), Seat heater switch passenger side, Overhead console, Electrochromic inside mirror unit (17700), Moonroof opening panel unit |
| 16 | 15A | Multi-function switch |
| 17 | 10A | Radio (18806) |
| 18 | 10A | Temperature blend door actuator (19E616), Function selector switch assembly (19B888), Daytime Running Lamps (DRL) module, Driver Door Module, Heated seat module driver side front (14C724), Heated seat module passenger side front (14C724) |
| 19 | 10A | Left-hand low beam headlamp |
| 20 | 10A | Digital Transmission Range (DTR) sensor (7F293) |
| 21 | 10A | Right-hand low beam headlamp |
| 22 | 10A | Passenger Airbag Deactivation (PAD) indicator, Restraints control module (14B321), Occupant classification sensor module |
| 23 | 15A | Multi-function switch |
| 24 | 10A | Passive anti-theft transceiver, Ignition coil relay, PCM power diode |
| 25 | 10A | Autolamp/sunload sensor (13A018), Adjustable pedal switch, Exterior rear-view mirror switch (17B676), Door lock switch driver side (14028), Door lock switch passenger side (14020) |
| 26 | 10A | Instrument cluster, Lighting Control Module (LCM), Overdrive cancel switch, Rear defroster relay coil |
| 27 | 20A | Data Link Connector (DLC) (14489), Cigar lighter front (15055) |
| 28 | 7.5A | High-mounted stop lamp (13A613) |
| 29 | 15A | Radio (18806), CD changer (18D806) |
| 30 | 15A | Multi-function switch (13K359) — Stop lamps |
| 31 | 15A | Multi-function switch (13K360) — Hazards |
| 32 | 10A | Rear window defrost switch (18578), Exterior rear-view mirror left, Exterior rear-view mirror right |
| 33 | 10A | Fire suppression manual switch, Fire suppression module |
| R | RELAY | Rear window defrost relay (C2021) |
Legend
- # — Terminal Position
- ABS — Anti-lock Brake System
- ACC — Accessory
- AMP — Terminal Amperage
- DDM — Driver's Door Module
- DLC — Data Link Connector
- DRL — Daytime Running Lamps
- DTR — Digital Transmission Range
- EATC — Electronic Automatic Temperature Control
- FUNCTION — Circuit Function
- I/P — Instrument Panel
- LCM — Lighting Control Module
- MFS — Multi-Function Switch
- PAD — Passenger Airbag Deactivation
- PATS — Passive Anti-Theft System
- PCM — Powertrain Control Module
- R — Relay
- RASM — Rear Air Suspension Module
- VAPS — Variable Assist Power Steering
Known Issues & TSB Reference
The items below are documented issues Mercury/Ford acknowledged for the 2006 Grand Marquis through Technical Service Bulletins (TSBs), extended warranty coverage, or well-established pattern failures. Full TSB text is available through ALLDATA, Mitchell1, or your dealer's service department.
4R75W — TCC Application in 2nd Gear (Hesitation / Lack of Power)
Affected: 2005–2006 Mercury Grand Marquis, Ford Crown Victoria, Lincoln Town Car. Some vehicles exhibit a stumble or power drop shortly after accelerating from a stop, most noticeable at light throttle between 15 and 30 mph. The cause is premature Torque Converter Clutch (TCC) lockup in 2nd gear. The fix is a PCM reflash. On a 2006 Grand Marquis with unexplained low-speed hesitation and no misfire codes, start here before chasing anything else.Reference: Ford TSB — 4R75W TCC Application in 2nd Gear, 2005–2006 Panther platform vehicles
4R75W — Forward Clutch Slipping / Metal in Fluid
Affected: 2005–2006 Ford vehicles with 4R75W. Excessive slipping in all forward gears, sometimes with metallic particles in the fluid. Repair is forward clutch drum replacement plus a PCM reflash (program 06B06). Dark or metallic ATF on a slipping 2006 Grand Marquis means start at the forward clutch before drawing any other conclusions.Reference: Ford TSB — 4R75W Forward Clutch Slipping, 2005–2006 Ford vehicles
Lighting Control Module (LCM) — Solder Joint Failure
Affected: 2003–2005 Ford Crown Victoria and Mercury Grand Marquis (extended warranty); 2006 Grand Marquis units with early build dates may also exhibit this. The LCM relay develops a cracked solder joint at the circuit board connection, causing intermittent or total failure of headlamps, taillamps, or other LCM-controlled lighting. The LCM is located behind the driver's kick panel. Inspect the relay solder joint before replacing the module — a quality re-solder is the correct fix.Reference: Ford Extended Warranty Coverage — LCM relay solder joint failure, 2003–2005 Crown Victoria / Grand Marquis
Electronic Throttle Control (ETC) — Diagnosis Procedure
Affected: 2005–2006 Grand Marquis and other ETC-equipped Ford/Mercury/Lincoln vehicles. Ford's revised PC/ED manual states that the ETC_ACT and ETC_DSD PIDs should not be used to diagnose electronic throttle body concerns. Before replacing the throttle body or PCM on a wrench-light complaint: clean the throttle bore and plate, inspect APP sensor connectors at C175B, and verify TPS1 (C175E pin 19) and TPS2 (C175E pin 29) are tracking each other within spec.Reference: TSB — ETC Diagnostic Procedure Revision, 2005–2006 model year vehicles
MIL On — Misfire and Lean Codes (P0305, P0316, P0171, P0174)
Affected: 2005–2006 Mercury Grand Marquis. MIL may illuminate with misfire codes (P0305 / P0316) and lean codes (P0171 / P0174), particularly after extended idle. Root causes include carbon buildup at the throttle bore on DBW units, worn or fouled spark plugs, or failing COP boots allowing arcing. Check COP boots at C175E pins 1, 12, 24, 35, 38, 39, 42, and 43 for cracking or carbon tracking before pulling plugs. Plugs are Motorcraft SP-413, gapped at 0.054 in.Reference: TSB — MIL On with P0305/P0316/P0171/P0174 — 2005–2006 Grand Marquis
Coil-on-Plug (COP) Ignition — Misfire Diagnosis
Affected: 2006 Grand Marquis and other 2006 Ford/Mercury/Lincoln COP-equipped vehicles. Eight individual DG-508 coils — no distributor. Common failure patterns are cracked or carbon-tracked boots, weak coil output on high-mileage units, and plug-to-boot gap migration. A sustained COP misfire that sets P030X codes without a boot inspection isn't complete. A bad COP can also backfeed voltage spikes through C175E into PCM output drivers. Inspect boots and plug condition together before replacing coils.Reference: TSB — COP Ignition Misfire Diagnostic Tips, 2006 model year vehicles
Fog Lamp Circuit — 2006 Addition Notes
Affected: 2006 Mercury Grand Marquis (first year with factory fog lamps). The fog lamp circuit is fed by BJB fuse #16 (15A) and switched through relay #205 in the BJB relay bank. If fogs are inoperative, start at #16 and #205 before chasing the switch or bulbs. On 2005 Grand Marquis units, positions #16 and #205 are not present in the fog lamp configuration — don't use the 2005 diagram to trace a 2006 fog lamp fault.Reference: AllData — 2006 Mercury Grand Marquis electrical, fog lamp circuit
Scheduled Maintenance Intervals
The intervals below reflect Ford's Normal Schedule for the 2006 Grand Marquis as published in the Scheduled Maintenance Guide covering the Crown Victoria, Grand Marquis, and Town Car. If the vehicle served in taxi or livery duty, apply the Special Operating Conditions schedule — engine oil every 3,000 miles / 3 months, ATF every 30,000 miles. The LS Ultimate's rear air suspension should be inspected at every major service for line cracks and compressor filter condition, even without a specific Ford-published interval.
| Service Item | Normal Interval | Notes |
|---|---|---|
| Engine Oil & Filter | Every 5,000 miles or 6 months | SAE 5W-20 — 6 qts with filter. Taxi/livery: every 3,000 mi or 3 months |
| Tire Rotation | Every 5,000 miles | Inspect for wear at each rotation |
| Engine Air Filter | Every 30,000 miles | Motorcraft FA-1783 — replace sooner in dusty conditions |
| Fuel Filter | Every 30,000 miles | Motorcraft FG-986B — heavy use: every 15,000 miles |
| Spark Plugs | Every 100,000 miles | Motorcraft SP-413 — gapped at 0.054 in. Do not reuse if COP boots are cracked |
| PCV Valve | Every 100,000 miles | Replace at same interval as plugs |
| Serpentine Drive Belt | Inspect at 100,000 miles | Motorcraft JK6-926 — replace if cracked, glazed, or fraying |
| Engine Coolant | First change at 6 years or 100,000 miles | Motorcraft Premium Gold (yellow) — then every 3 years / 50,000 miles after |
| Automatic Transmission Fluid | Inspect at 15,000 mi — change at 150,000 miles | Mercon V only. Taxi/heavy use: every 30,000 miles |
| Brake Fluid | As needed / inspect annually | DOT 3 — replace if dark or boiling point degraded |
| Brake System Inspection | Every 15,000 miles | Pads, rotors, lines, hoses, parking brake |
| Rear Axle Lubricant | Inspect — synthetic fill considered "for life" | Taxi/livery: replace every 100,000 miles. Add XL-3 friction modifier for Traction-Lok (3.27 axle) |
| Power Steering Fluid | Check at every oil change | Mercon ATF — ~2 pints capacity |
| Air Suspension (LS Ultimate) | Inspect at every major service | Check compressor intake filter, lines, and air bags for cracks or leaks |
| Cooling System Hoses | Inspect at every major service | Replace heater hose assembly at first sign of seeping — Motorcraft KH428 |
Other Mercury Grand Marquis Years
Other Panther Platform Models
Data Disclaimer & Limitation of Liability
Read before using any data published on this site
Informational use only. All fuse assignments, relay positions, wire color codes, pin assignments, circuit numbers, connector identifiers, engine specifications, transmission specifications, torque values, maintenance intervals, and technical service bulletin references published on this site are provided for informational and reference purposes only. This data is not a substitute for a factory Ford, Lincoln, or Mercury service manual, an ALLDATA or Mitchell1 subscription, or the judgment of a qualified, licensed automotive technician.
No warranty. Data provided as-is. Riot Mind Studios, LLC makes no representations or warranties of any kind — express, implied, or statutory — regarding the completeness, accuracy, currency, or fitness for a particular purpose of any data published on this site. All information is provided strictly on an "as-is" and "as-available" basis. We do not warrant that any data point is free from error, omission, or misprint. We do not warrant that this data reflects the current production configuration of any specific vehicle.
Vehicle condition and prior modifications. The Panther Platform vehicles covered by this database (2003–2011 Ford Crown Victoria, Lincoln Town Car, Mercury Grand Marquis, and Mercury Marauder) are aging vehicles with decades of potential service history. Individual vehicles may have been subject to dealer modifications, police upfitter conversions, aftermarket electrical work, wiring repairs, fuse upgrades, or component substitutions that are not reflected in factory documentation or in the data published here. You are responsible for verifying all data against the actual condition of your specific vehicle before performing any repair, diagnostic test, or electrical work.
Model year and trim variation. Fuse assignments, relay types, PCM pin functions, and circuit configurations vary across model years, between trim levels (LX, P71/Police Interceptor, Executive, Signature, GS, LS, HPP, etc.), and in some cases between build dates within the same model year. Data that is accurate for one configuration may be incorrect or inapplicable for another. Always cross-reference this database against a source that is specific to your vehicle's model year, trim level, and build date.
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