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Mercury Mountaineer electrical issue

Posted by ralmoy (My Page) on
Sat, Oct 17, 09 at 13:59

Hi all hope someone can help...my 2002 mercury moutaineer. All of a sudden on friday. The following stopped working...The instrumentement cluster is dead..The Windows all don't go down nor up, The sunroof is dead also and the Radio is dead...The headlights work but only when i turn them on by hand the automatic is not working. also seems all interior lights don't work. I checked all fuses in the passenger compartment fuse box next to the steering column under the dash...all fuses are OK...someone from a parts store said it could be a main fuse in the engine compartment...I checked all the fuse in the engine fuse box all seem fine...someoone suggested it is a relay or a module...the only thing i cound narrow down was what is called a PTEC relay...but can't tell if it bad because its a black box that fits into slots like a fuse in the fuse box in the engine...any ideas...Thank you!


Follow-Up Postings:

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RE: Mercury Mountaineer electrical issue

Its my guess that you lost a major ground connection, a connection that is common to the items that quit. You'll need a wiring diagram and connector list to chase down where all these are located, but for a shot in the dark, check out the engine grounding strap. I hope that the bad connection is not behind the intrument panel.

Another possibility is the ignition switch.

You may have to resort to chasing the circuits with a voltmeter, moving through the wiring maze until you find the location where the circuit is lost.


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RE: Mercury Mountaineer electrical issue

Common to all of the affected circuits is the "Gem" (Generic Electronic) module. (On some it becomes the "FEM" Front Electronic Module). We can call it the GEM for now, the GEMs functions ultimately get split into several modules when Ford switches to the FEM/REM system, and off hand I don't recall what year the switch was made. The GEM controls the communication bus that the auto headlamps need to operate, and so does the radio and the instrument cluster. Diagnostics start by attempting to communicate to any and all of the vehicle modules through the ALDL, and this does require the factory level scan tool, the Ford IDS.


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