GEM Fuse Blowing

If you replace the fuse, then open the passenger door instead of the driver's door, does the fuse also blow?

If yes, does it also blow if you have removed the bulb from the dome lamp (I accume you have a coupe, not a convertible)?

I know you have to waste some fuses to do these tests, but it is a lot easier than ripping the car apart to look for the cause.

Were any repairs or mods done to the vehicle just before the problem first appeared?

vld said:

I have tried and tried to track this problem down and am now at a complete loss. The fuse that controls my interior lights and GEM blows the instant it makes contact. The only way it goes in is if I disconnect the battery. Problem with this is as soon as I open the door (after reconnecting the battery) the fuse pops again. Any ideas? The fuse is the #7 fuse I believe.

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For the fuse to blow you have a short to ground somewhere.

One of the door switches could be garbage and shorting to ground. See if it still pops with the bulb out.

The two door switches connect between the GEM and ground. When either closes, the GEM outputs 12V to the dome lamp. You could have a short to chassis in the dome lamp assembly, the wire leading to it (less likely), or within the GEM itself.

Behind the passenger-side cowl panel, about half-way up, approximately at the level where the wires pass into the rubber conduit to the door, there is a 3 pin connector, gray in color. This connector carries all connections from the GEM to the dome/courtesy lights. If you pull apart that connector, and the fuse no longer blows, the problem is most likely in the light assembly. If the fuse still blows, my money is on the GEM.

GEM failures, however, are very rare. In 5 years on this and other Mustang boards, I have yet to see a reported GEM failure. If anyone has recently done any kind of work under the dash, I would immediately suspect damage to a wire before the GEM.