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-   -   97 z3 onboard computer, gas gauge and temp gauge quit working (

LoneWolf87 11-15-2012 01:38 PM

97 z3 onboard computer, gas gauge and temp gauge quit working
1997 Z3. Need a little help. For no apparent reason, my onboard computer quit working, no lights, zilch. And the gas gauge went to empty, and low fuel warning light came on, and the temp gauge quit working. I checked all the fuses related to instument lights and onboard computer and they all appear to be good. I pulled and replaced each fuse a couple times in case there is a bad connection, and no change. Anything else you know of that can make all these go on the fritz at the same time? I appreciate any help, because the only documentation I have is the owners manual. ands its basically worthless for this sort of thing.:(

Monolith 11-15-2012 04:58 PM

Open the trunk and slice open the wire bundle on the driver's side going from the trunk to the trunk lid. You're looking for any signs of broken wires or bad insulation.

wifesauto 11-16-2012 06:08 AM

test electrical items with a good DVOM or test light...............DO NOT rely on the MK1 eye ball tester

Monolith 11-16-2012 08:49 AM

In certain cases the MK1 is sufficient:

LoneWolf87 11-16-2012 09:49 AM

Thanks guys for taking time to post possible solution. I haven't sliced into the wiring loom yet, but I was really surprised at the size and amount of wires. As far as I can tell, only the upper stop light and trunk illumination light is all that is in the trunk. But, I'll check into it. A short somewhere sounds logical.

Monolith 11-16-2012 09:53 AM

Don't be fooled by what's just in the trunk. Those wires affect the circuits you've described above... believe it or not. So check there first.

LoneWolf87 11-16-2012 11:41 AM

OK, I have a new clue. I checked the wiring harness where it undergoes the most stress and maximum bend when the trunk is opened and closed and did not find any evidence of insulation deteriorization , fraying or broken wires. But I only peeled back about a half inch of the black plastic protective shroud. However, I did have the idea to check the upper stop light and shoot, it wasn't working , nor were the other two stop lights. So I have no brake lights whatsoever, and apparently the two side stop lights are not energized through this particular piece of wiring harness. Since I didn't know stop lights were not working, I did not check if they have a separate fuse. I'm gonna go check that now.

Monolith 11-16-2012 12:00 PM

Just to give you an idea of just some of the issues caused by the trunk wires:

"Last week or so I posted regarding a fuse that kept blowing after the front bumper had been removed and replaced. The right front side marker and amber light next to the headlight were out as well. After a lot of head-scratching we found the problem. It was completely unrelated to the front bumper, just strange timing. There is a cluser of about 12 wires that comes from the trunk and goes into the trunk lid. It takes a sharp bend at a clip that holds it to the hinge. This was the problem. We opened up the sheath and found that two wires were broken apart and all the rest were showing copper and randomly shorting. Problem solved."

mnguyen84 11-16-2012 06:16 PM

i'm beginning to get weird electrical issues on my 96 z3 too. i'll have to check under the hood soon.

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