Door ajar light not working

hhspaladin

New Member
Jul 25, 2010
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Hello all, I'm having an issue with my 2004 V6. None of the things that usually happen when the doors are opened are working. The dome light doesn't come on except when the doors are unlocked, and the door ajar light and keyminder don't come on when the doors are open. I know this model mustang has the door ajar switch built into the door and latch, but both can't be out at the same time, right? Any help on this issue would be greatly appreciated! Thank you!
 
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Note, your MY Mustang has only a single door switch (for each side). The door ajar switch goes to the generic electronic module (GEM). It is the GEM that decides what to do.

I assume that the dome light comes on when the doors are unlocked with the remote FOB. This confirms that the fuse and the dome light circuit is working.

However, since there is only a single door ajar switch that controls all door ajar functions, IMO it is possible that the door ajar switch is bad and is the source of the problems.
 
That was my question. Because the dome light does work when the doors are remote unlocked, yet the door ajar light/dome light don't come on when either door is open, does that mean that both door ajar switches are bad?
 
If you don't think both door switches could go bad at the same time (which is not a far fetched idea), then let's look at the other possibilities.

The wiring diagram indicates that both door switches are grounded in different spots. So that's not it.

The GEM itself is grounded at G204 which is the same ground that the radio uses. It is located near the center console (left of the hump).

So any recent radio work? Check the grounds just to be sure.

If it is not a bad GEM ground then it is likely to be a bad GEM module.

To double check, try grounding GEM pin 13 (YE/BK). This should simulate the door ajar switch. If the key minder still doesn't work, then it has to be a bad GEM.
 
I just can't believe that I would have bad enough luck to have both switches go out. But then again I have horrible luck, so who knows :/. Unless radio work was done before I got the car, there has been none. It still has the factory Mach audio system and that's been in place for at least a year.

Assuming I'd like to test the GEM pin you mentioned, how would I go about that? Where is the GEM itself located?
 
The door ajar switch is located INSIDE the door. I believe it is located near the latch. I personally have never seen it.

The GEM is located in slightly different locations depending upon model year. It's well up under the dash. Start by looking to the right of the steering column.