All You need to know about the Mustang CCRM
What does a CCRM do?
The Mustang CCRM, also known as the Constant Control Relay Module, is a module found on the 1994-2004 SN95 Mustang that provides vehicle power to the powertrain control module (PCM) for various components on the Mustang. These components include the following:
- Cooling Fan
- A/C Clutch
- Fuel Pump Driver Module (FPDM) power supply
- PCM Power relay
If you experience any issue where the PCM, cooling fan, air conditioner compressor clutch, or fuel pump is not getting power, the CCRM may be the culprit.
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Where is the CCRM Located?
The CCRM will vary depending on the model and year of your SN95 and New Edge Mustang.
- 1996-2004 - The CCRM is located on the inner fender of the passenger side. Removal of the wheel and inner fender liner is required to access the CCRM wiring.
- 1994-1995 - The CCRM is mounted to the overfill mounting bracket in front of the radiator fan.
How do I change the CCRM?
Once you determine the location of your CCRM based on the year model above, follow these instructions to replace your CCRM.
- Disconnect both battery cables from the battery.
- 1996-2004 - removal of the wheel and inner splash shield will allow you to gain access to the CCRM. 1994-1995 Mustang will have the CCRM on the overfill bracket.
- Remove the wiring harness connection using a 5mm socket. Once loosened completely, you can remove the wiring harness from the CCRM by pulling the harness away from the module.
- Remove the two 5.5mm bolts that retain the CCRM to the mounting bracket. This will allow you to remove the CCRM from the bracket completely. 1994-1995 Mustangs, removing the overfilled bracket will ease the installation, but it is unnecessary with the correct tools.
Are All CCRM Interchangeable?
It is always good to double-check the part number when installing a replacement CCRM. V6 and V8 CCRMs are different, and 2001-2004 are different from the older 1994-2000.
How To Diagnose A Bad Fuel Pump Relay
Before we discuss where to find the fuel pump relay, let's talk about how to diagnose the fuel pump relay on your Mustang. If the relay slowly malfunctions, the vehicle may gradually exhibit performance issues.
Here are some issues that your Mustang may be experiencing:
- The fuel pump won't have power if the fuel pump relay malfunctions. Even though the engine may still turn over when the key is turned, it won't be able to start because of a fuel shortage.
- Most fuel pumps emit a low-pitched hum or whine that can be detected from within the car if you listen carefully or from the outside of the car, close to the fuel tank. When the fuel pump relay malfunctions, power will be cut off, rendering the pump inoperable and silent when the ignition is turned on.
Where To Locate The Fuel Pump Relay
Now that we've covered the symptoms and issues, let's find the CCRM (or Constant Control Relay Module) location, which houses the fuel pump relay on your SN95 or New Edge Mustang.
- For 1994-1995 Mustangs, the CCRM is mounted to the overflow tank mounting bracket behind the radiator fan.
- For 1996-2004 Mustangs, the CCRM will be within the passenger front fender (unless your vehicle has been altered and modified by the previous owner). You'll have to remove the inner fender liner on the passenger side front fender. Once removed, you'll be able to locate the CCRM.
The photos shown below are for 1996-2004 Mustangs. However, the design and wiring of the CCRM are the same.
Fender removed for clarity
How To Fix A Bad Fuel Pump Relay
Be sure to check the fuel pump relay fuse before working on the CCRM. There is a chance that the fuse needs to be replaced. Check out the full list of every 1994-2004 fuse panel diagram here. We highly recommend replacing the entire CCRM versus opening it up and replacing the fuel pump fuse. Once you determine the location of your CCRM based on the year model above, follow these instructions to replace your CCRM.
- Disconnect both battery cables from the battery.
- 1994-1995 Mustang will have the CCRM on the overflow tank bracket. Remove the wiring harness connection using a 5mm socket. Once loosened completely, you can remove the wiring harness from the CCRM by pulling the harness away from the module. 1996-2004 - removal of the wheel and inner splash shield will allow you to gain access to the CCRM.
- Remove the two 5.5mm bolts that retain the CCRM to the mounting bracket. This will allow you to remove the CCRM from the bracket completely. 1994-1995 Mustangs, removing the overflow tank will ease the installation, but it is unnecessary with the correct tools.
