So I've seen a few 940 gas gauge problems over the years, from my experience at a local shop and fixing a small population of survivor cars here.

This one's kind of got me scratching my head. The car's a 93 945 non turbo (NA), typical US model.

The fuel gauge was intermittent and seems now that maybe it's quit completely. 3 years ago, when my friends bought the car from me it was working fine, even the low fuel light.

I thought, well maybe it's the 3 screws on the circuit board. Loosen, clean, tighten, that didn't fix it. Today I went deeper. I had a spare cluster pulled from a car with a charging problem. (Same year, 93 940.) I bought a good used cluster for that one and it's been on the road since. I remove and plug in the "dead" cluster and, on a short test drive, what do you know, the gauge works. Showed the approx 1/4 tank that was in the car.

OK, cool. I pulled it again, took it apart, swapped the gauge into our cluster, and... nothing. Hmm. Check screws, all ok. Swapped the voltage regulator thing from the back of the cluster. Still nothing. So maybe there's a problem in the flex circuit. I can try soldering or find another one I guess.

Part 2 of the problem, which I'll rule out with a replacement, is that the odometer AND speedo have now died. Inspecting the rear axle connector showed frayed wires. Not broken, but possibly shorting to each other or the suspension.

So I repaired the wire insulation under the car, checked continuity to the plug in the left rear wheelwell, ok. Not shorted, but both wires read 1 ohm or less from lower connector pin to upper connector pin.

Speedo still doesn't work. And it didn't work with the spare cluster either. I've seen a reference to another fuse under the dash outside of the fuse box, for ABS or near the ABS computer connector? I can't find it, if it exists.

All help appreciated. Thanks guys!

--Rob Bareiss
New London CT

--
89 244GL Turbo // 92 244 M47 \\ 90 745T // 76 242 Convertible

Have you seen these?

https://www.brickboard.com/RWD/volvo/456616/940/960/980/V90/S90/finally_permanent_fix_940_fuel_gauge_problem_archive.html

http://www.turbobricks.org/maint.php?content=art0031

Dan

Also, the "test" cluster in which the gas gauge did work, had previously been re-soldered by me. That may be why that circuit of it, at least, did work.

I never did correct the charging issue with that other car with this cluster. There's still something bad lurking in it.

I was thinking I would re-solder this cluster and see if anything behaves better. I may have access to another car for troubleshooting as well so might try a good car-bad car swap with both.

--Rob
--
89 244GL Turbo // 92 244 M47 \\ 90 745T // 76 242 Convertible

Those are great links! I hadn't seen either one. I agree with the tech in the TBricks one... these things are mysterious even to us curious, handy electrical guys, and it's frustrating when these fairly simple cars resist our attempts to fix them!!

Thanks Dan,
--Rob
--
89 244GL Turbo // 92 244 M47 \\ 90 745T // 76 242 Convertible

Rob
Hope that's the issue! So far I haven't had a 940 but I remembered reading these threads awhile back.
Dan