[V6-12v] Weird gauge problem - 1993 90Q - Help!

[apowell at colocougs.org]

Halfway through a 300-mile round trip to eastern Colorado last night, my wife's 193 90Q developed a
problem - I'm VERY interested in whether anybody's BTDT or knows a typical failure item that might
relate.

The problem is that a 15-amp fuse started blowing; when it blows, she has no gauges. No speedo,
tach, gas, temp, etc. And just to make it more interesting, the oil pressure warning light goes on
and off intermittently when the fuse it out. Of course, when this happened, she was 150 miles away
and it was after dark.

The fuse is OK as long as the car DOES NOT move, so working on the cell phone, I asked her to idle
the car for a while and see if the oil light came on. It didn't - so I told her to drive it home.
She got home OK with no expensive noises from the motor, so I'm confident the oil pump is working
OK. 

Here's the part I need to work on: as soon as she puts the car in reverse, POW! The fuse goes. I
need to find the short and get it fixed, because it's pretty tough to find a car with no gauges and
with warning lights going on and off. If it's driven without going into reverse, the fuse will
eventually blow, but it takes a while.

One possible related fact: for about six months, the power door locks have been engaging by
themselves, usually when the car is shifted either into first or reverse. We start the car, back out
of the driveway, and usually when we shift from reverse to 1st, we hear the door lock pump engage
and the doors all lock. It also often locks when we close the trunk. This habit puts me in mind of
the nasty trick that the type 44 chassis cars pulled with broken wires in the left-side of the wire
chase on the trunk lid, but I've checked the wires and don't see anything, although I haven't really
torn into it.

Thoughts? BTDT's? Places to start? The problem that I need to solve immediately is the fuse blowing
when the car goes into reverse. 
************************************
Al Powell
apowell at gocougs.wsu.edu
1958 Fiat 1200 Transformabile Spyder
1983 Datsun 280ZX Turbo
1993 Audi 90Q
1991 Camaro RS Convertible
1997 Chebby Blazer
1999 Chebby Blazer
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