Ford GEM (Generic Electronic Module) Troubleshooting

This applies to both Ford GEM (Generic Electronic Module) also known as Four-Wheel Drive Control Module

Upon re-installation, if you're still unable to communicate with the GEM, please ensure that the Fuse Box it mounts to is cleaned and functioning correctly. 

Due to its location both the Fuse Box and GEM are vulnerable to water intrusion. If enough water damage occurs to either of these units, they may be unrepairable. 

Step 1:

Disconnect all the fuses, relays, and connectors going to the Fuse Box. Inspect for any signs of corrosion including white, grey, or green residue on all the pins. 

Step 2: 

Using an Automotive electronics connector cleaner like the one from CRC 'QD Electronic Cleaner' that can be purchased at any automotive store, spray all the harness plugs, pins of the GEM, Fuse Box, Relays, and Fuses. 

Di-Electric grease is also recommended to create a barrier should water get in again through the wires. 

Step 3: 

Using a gasket maker, it is recommended to seal off openings and any other vulnerable areas on the Fuse Box and possibly a cover over the harness wires to divert any water from pouring on the Fuse Box and GEM. 

Step 4: 

Using an OBDII scan tool. Scan the GEM (Generic Electronic Module) and ensure that the module is communicating with your scan tool. Clear any codes and run the vehicle to see if the issues are resolved.