Like it says i turn on my wipers and the gauges stop working properly, tach goes nuts and so do all the other gauges, same goes (kinda) for my hazards, BTW my blinkers dont work
Does the dash lighting go nuts as well or just the needles? It's possible that the power to operate the wiper motor is overloading the dash gauges but I would assume that's very unlikely. Do you have aftermarket gauges as well as stock ones?
You'll probably want to take the dash apart and check out the wiring. Never know if someones done some kind of hillbilly wiring job. I assume that's not the case though from looking through you're build thread
My first inclination would be to get under the dash and check and reseat (even if they don't look like they need it), all your grounding wires. Do the same for grounding wires up against the firewall in the engine bay.
I'd encountered a similar problem and actually ADDED a couple grounding wires. Since you're able to pinpoint your symptoms to running the wiper motor, try adding one to the wiper motor casing.
ive checked everything in the wiring harness, everything was either fixed or added new recently in the past 3 months, im not sure about the lights though, its been too bright to tell while working on it, and all the engine grounds i just did 3 days ago in 4ga and very well prepped everything
I am having a similar problem on my 89 gt convertible, I have changed the multifunction switch 3 separate times the wiper motor 3 separate times and the intermediate switch below the steering column twice... I have all light all gauges working, fuse's are all good, the wipers work when I press the end of the multifunction switch for the windshield washer like they should but that is it they do not work slow speed or high speed any help or ideas would be greatly appreciated
"gages go nuts" please explain - do they go high, or go low, or do they go up and down in sync with the wiper blades, or do they just dance around in random fashion?