The 1999–2004 Mustang GT CCRM is located in the right-front fender area beside the air-cleaner/intake route. This guide covers its year-specific connector pin assignments, Ford diagnostic specifications and documented replacement coverage.
Applies to stock 4.6L 2V GT wiring. V6, Mach 1, Cobra and Cobra R applications require their own diagrams. Selected factory checks below must be used with the matching symptom and pinpoint-test branch.
Stop buying modules before testing the circuit
A Mustang that won’t start, a cooling fan that won’t cooperate and an A/C clutch that won’t engage can send you looking for the Constant Control Relay Module. Finding it is useful. Deciding it’s guilty requires more than somebody in a forum typing “CCRM” in capital letters.
For the 1999–2004 Mustang GT, start with the correct year diagram. The connector name changes during this run, the A/C circuit changes, and Ford’s high-speed fan relay resistance specification changes too. One copied pinout and one generic resistance number won’t cover those differences accurately.
Where is the Mustang GT CCRM?
The six year-specific Ford location illustrations place the GT module at the right-front fender area, adjacent to the air-cleaner/intake side of the engine compartment. Right means the vehicle’s right side: passenger side on a U.S. left-hand-drive Mustang. Do not reverse it because you are facing the engine.
The illustrations identify the module and connector as follows. They establish its position, not a complete removal procedure or access-fastener torque.
| Year | GT location shown in its Ford illustration | CCRM connector |
|---|---|---|
| 1999 | Right-front fender area beside intake/air-cleaner route | C192 |
| 2000 | Same right-front fender area | C192 |
| 2001 | Same right-front fender area, view 151-6 | C192 |
| 2002 | Same right-front fender area, view 151-5 | C1262 |
| 2003 | Same right-front fender area | C1262 |
| 2004 | Same right-front fender area, view 151-6 | C1262 |
Sources: the individual location and connector references in the year-by-year source table below. The 1999 location page also carries generic wording about a bracket behind the coolant reservoir; the engine-specific illustration is the clearer locator for this GT application.
What the CCRM supplies
Ford describes the module as part of the PCM/engine-control power system, cooling-fan control and A/C clutch control. Its fuel-system relay supplies the fuel-pump driver module (FPDM) in the illustrated GT circuit. That does not make the CCRM and FPDM the same component.
Follow the entire affected circuit. Having voltage at a module supply terminal does not prove that its output, wiring, downstream device and control command are all working.
GT CCRM pin assignments
This is a functional summary checked against the six year-specific connector charts, plus the relevant Ford circuit diagrams. Grouped cavities share the listed function; they remain separate physical terminals. Circuit identifiers and colors are aids to identification, not substitutes for checking the numbered cavity.
| Pin(s) | Circuit / color | GT function |
|---|---|---|
| 1, 2 | 229 / RD-OG | Low-speed fan output |
| 3, 4 | 554 / YE-BK | Fan-circuit battery supply |
| 5 | 238 / DG-YE | Relay output toward FPDM supply path |
| 6, 7 | 638 / OG-LB | High-speed fan output |
| 8, 10 | 38 / BK-OG | Battery supply |
| 9 | — | Unused in these charts |
| 11 | 1059 / LB-OG | Fuel-system relay battery supply |
| 12 | 361 / RD | PCM/engine-control power output (VPWR) |
| 13 | 20 / WH-LB | Ignition Start/Run input |
| 14 | 228 / DB | Low-speed fan control |
| 15 | 570 / BK-WH | Ground |
| 16 | 1205 / BK | A/C clutch ground path |
| 17 | 639 / LG-VT | High-speed fan control |
| 18 | 1205 / BK | Ground on these GT applications |
| 19, 20 | — | Unused in these charts |
| 21 | 198 / DG-OG | A/C-related supply; circuit arrangement changes by year below |
| 22 | 331 / PK-YE | A/C relay control |
| 23 | 347 / BK-YE | A/C clutch output |
| 24 | 1118 / RD | PCM/engine-control power output (VPWR) |
RD red; OG orange; YE yellow; BK black; DG dark green; LB light blue; DB dark blue; WH white; LG light green; VT violet; PK pink. A slash or dash separates the main color from its stripe.
Connector viewpoint matters. A harness connector and the module’s mating connector are mirror images when viewed face-on. The Ford 2000 and 2004 pinpoint schematics explicitly show both. Match the locking/key features and cavity numbers to the relevant drawing; a text table cannot establish connector orientation.
Source reconciliation: some earlier connector legends describe pin 24 as always-hot power. Ford’s operational/pinpoint schematics identify pins 12 and 24 as VPWR on the power-relay output side. This table follows the circuit function, rather than converting the older legend into a claim that pin 24 is an unconditional battery feed.
The A/C difference between 1999–2000 and 2001–2004
The 1999 Ford PCED description and the 2000 4.6L schematic show a normally closed WOT A/C cut-off arrangement. The 2001 4.6L A/C diagram shows the later normally open clutch-relay arrangement, also shown in the 2002–2004 schematics.
| GT years | Verified arrangement | What that changes |
|---|---|---|
| 1999–2000 | Normally closed A/C cut-off relay; pin 21 is in the pressure-switch/request supply path | Do not apply later A/C control assumptions |
| 2001–2004 | Normally open A/C clutch relay; pin 21 has its battery-fed supply path | Select the matching diagram and test branch |
The 2001 A/C drawing is especially useful: it shows C192, pin 12 feeding the coil, pin 22 as its control, pin 21 as the contact supply and pin 23 as the clutch output. This establishes an electrical difference before the connector designation changes to C1262 in 2002. The connector name change and the A/C change occur at different year boundaries.
Do not ground or power a terminal using a different year’s instructions. This article does not prescribe a universal jumper test.
Ford test specifications, with their conditions
The numbers below summarize selected factory checks. Enter the appropriate pinpoint branch for the symptom or preceding failed test; these are not independent verdicts that any single successful reading proves the entire module good or bad.
For meter setup, see how to use a multimeter. Keep resistance measurements on de-energized circuits with the specified components disconnected. For voltage measurements, use the stated key position and harness side. Keep clear of the fan while commanding it.
PCM/engine-control supply concern
| Year | Verified continuity setup at the start of Test X | Supply check in X2 |
|---|---|---|
| 1999 | IAC/CCRM disconnected; check IAC VPWR path to CCRM 12/24; factory branch asks whether either reading is below 5 Ω | Harness 8/10 battery supply and key-on, engine-off 13: above 10.5 V |
| 2000 | Same IAC-to-CCRM setup in its Test X | Same 10.5 V threshold |
| 2001 | Same IAC-to-CCRM setup in its X1–X3 sheet | Same 10.5 V threshold |
| 2002 | Same IAC-to-CCRM setup in its X1–X15 sheet | Same 10.5 V threshold |
| 2003 | Fuel-injector VPWR path to CCRM 12/24; injector/CCRM disconnected and scan tool removed; below 5 Ω at the applicable branch | Same 10.5 V threshold |
| 2004 | PCM and CCRM disconnected; harness VPWR-to-VPWR continuity below 5 Ω | Key on; B+ and IGN Start/Run to ground above 10.5 V |
For the earlier X3 supply-fault branch, Ford measures between harness pin 8 (B+) and pin 15 (ground), with a threshold above 10.5 V. The 2004 X3 sheet specifies the equivalent B+-to-GND check by circuit name. Follow the preceding branch and connector reference; do not use that isolated reading as a complete fuel-pump, fan or A/C diagnosis.
10.5 V is a diagnostic threshold in those steps, not a target battery charging voltage or a universal specification for every output.
High-speed fan relay coil
These are component-side checks with the CCRM disconnected, for the applicable two-speed fan diagnostic branch.
| Year | Ford branch | Checked terminals/circuits | Specified resistance |
|---|---|---|---|
| 1999 | X15, P1479 | CCRM 17–24 | 65–100 Ω |
| 2000 | X15 | CCRM 17–24 | 65–100 Ω |
| 2001 | X15 | CCRM 17–24 | 65–100 Ω |
| 2002 | X15 | CCRM 17–24 | 65–100 Ω |
| 2003 | X15, P1479/P0481 | CCRM 17–24 | 65–110 Ω |
| 2004 | X4, P1479/P0481 | VPWR–HFC; connector reference identifies 24–17 | 65–110 Ω |
Ford’s diagnostic branch continues with internal-short and harness/control checks when the coil passes. A passing coil alone does not prove relay contacts can carry the load. Our automotive voltage-drop testing guide explains why circuit performance under load matters; it does not replace the Ford pinpoint procedure. For 2003, the internal-short check between 17 and 15 includes a meter-polarity note; copying an earlier sheet without that note can change the conclusion.
Cobra and V6: why this GT table needs a boundary
The 2003 and 2004 Ford C1262 charts explicitly give Cobra pin 18 a white wire, circuit 866, for fuel-pump relay control, while the other listed configuration uses black circuit 1205 ground. Treating every pin 18 as ground is therefore wrong.
The 2004 Ford pinpoint introduction also separates 3.8L/3.9L and 4.6L schematics. Use those specific diagrams for a V6. The GT table does not apply to V6 fan outputs, Cobra fuel-pump control, Mach 1 wiring or the 2000 Cobra R.
Replacement interchange: select the exact replacement product
A newly designed replacement can be cataloged for multiple original modules. That does not prove the original Ford modules were interchangeable with each other.
The following is verified published replacement coverage, not an OEM interchange guarantee or a VIN-specific parts lookup:
| Application | Source-supported replacement information |
|---|---|
| 1999–2000 GT 4.6L | NPD’s M-12B577-101B lists 1996–2000 4.6L coverage and includes F6SZ-12B577-AA among the original assemblies it replaces |
| 2001–2004 GT 4.6L | NPD M-12B577-135B lists 2001–2004 4.6L coverage and replacement of 1R3Z-12B577-AA; NPD’s original-part listing separately identifies that Ford service number for this range |
| 1999–2004 3.8L V6 | NPD M-12B577-135B lists this application and XR3Z-12B577-AA; its older M-12B577-125A listing points to 135B |
| 2004 3.9L V6 | Not explicitly covered by the above NPD 3.8L wording; require an explicit 3.9L application match rather than extending it ourselves |
NPD’s 135B heading starts at 1999 because it includes the V6. Its detailed application list starts the 4.6L coverage at 2001. Reading only the headline would select the wrong coverage for a 1999–2000 GT.
LMR’s current LRS-37517 page independently states 2001–2004 4.6/V6 coverage and excludes 1994–2000. That statement applies to that product, not every replacement CCRM sold elsewhere. Blue Streak’s manufacturer bulletin also distinguishes RCM54 (2001–2004 Mustang) and RCM55 (1999–2004 Mustang), but provides no engine-level interchange in that bulletin; do not invent it.
Select by exact vehicle application, installed module identification and any catalog restrictions. A matching connector housing is not enough. No exhaustive engineering-number/suffix supersession chain, 3.9L interchange or Cobra R interchange has been verified here.
Related My Pro Street guide
For the older demonstration, see How To Check Your Ford Mustang CCRM. That article demonstrates an earlier 1996 Cobra application; use the year-specific references here for the 1999–2004 GT.
Mustang GT CCRM FAQs
Where is the CCRM on a 1999–2004 Mustang GT?
Ford’s year-specific illustrations place it in the right-front fender area beside the air-cleaner/intake route. The connector is C192 for 1999–2001 and C1262 for 2002–2004.
Are 1999–2004 Mustang GT CCRMs all interchangeable?
Do not assume so. The A/C relay arrangement changes for 2001, and replacement catalogs distinguish the earlier and later 4.6L applications. Match the exact replacement product and vehicle application.
What resistance should the high-speed fan relay coil have?
The factory checks summarized here specify 65–100 Ω for 1999–2002 and 65–110 Ω for 2003–2004, measured at the disconnected module’s specified VPWR/HFC terminals. Use the matching year’s pinpoint branch.
Is the CCRM the same as the fuel-pump driver module?
No. In the GT circuit shown, a relay in the CCRM supplies the separate FPDM. Diagnose the complete supply and control path before replacing either module.
Sources and service references
The technical references below are Ford service documents and original manual illustrations. Replacement coverage is attributed to the supplier’s own catalog.
| Year | Location illustration | Connector chart | Pinpoint tests |
|---|---|---|---|
| 1999 | Ford 1999 location | Ford 1999 connector | Ford 1999 Test X |
| 2000 | Ford 2000 location | Ford 2000 connector | Ford 2000 Test X |
| 2001 | Ford 2001 location | Ford 2001 connector | Ford 2001 Test X |
| 2002 | Ford 2002 location | Ford 2002 connector | Ford 2002 Test X |
| 2003 | Ford 2003 location | Ford 2003 connector | Ford 2003 Test X |
| 2004 | Ford 2004 location | Ford 2004 connector | Ford 2004 Test X |
Additional direct references:
- Ford 1999 Test X introduction and diagrams.
- Ford 1999 PCM output descriptions, A/C and fan operating logic.
- Ford 2001 4.6L A/C circuit, drawing 54-3.
- 2000 Ford Test X 4.6L schematic, AA0923-G, normally closed A/C relay.
- 2003 X1–X2 sheet, injector-path continuity and supply checks.
- 2003 X3/X15 sheet, 65–110 Ω and polarity note.
- 2004 X1–X2 sheet, PCM/CCRM-disconnected continuity setup.
- 2004 X3–X4 sheet, 65–110 Ω.
- NPD M-12B577-101B, supplier’s detailed application and original-part list.
- NPD M-12B577-135B, detailed engine/year application and XR3Z/1R3Z replacement claims.
- NPD M-12B577-125A, supplier transition to 135B.
- NPD original 2001–2004 4.6L listing, 1R3Z-12B577-AA.
- LMR LRS-37517, current stated product fitment; does not establish OEM-to-OEM interchange.
- Blue Streak manufacturer bulletin, October 2016, page 24, two distinct Mustang replacement entries; engine details not supplied.
