i have a 94 mx3 gs and i cant get my gauge cluster lights to work. my turn signals, highbeam indicator, warning lights light up but my illumination lights dont. could installing my stereo have had anything to do with this?? I've tried looking at the wiring but its all connected and my outer lights all come on so its not a relay.. any help would be appreciated cuz im outta ideas

 

Depends on what wires you may have used for the stereo. Some stereos have the option to dim lights with lights in the car. If you attempted to tap into dimmer, you may have interrupted current.
I'd suggest checking the dimmer control either way...or fuse, though i don't recall if there's a fuse solely for instrument lights

 

Cut the ground wire coming out of the aftermarket stereo. The car harness does not contain a ground wire at the radio,it grounds through the chassis/antenna. as projex said the dimmer is most likely fried as the wire you thought was a ground was hot with the lights on to dim the radio face at night.

 

Ah, I didn't think of the tricky ground wire itself. If it is connected to anything that isn't a ground, it would trip something out... If this is the case, run the stereo's ground wire to a good ground, else stereo won't work.

 

It will work. It will ground through the chassis/antenna. I never use the ground wire as it can cause feedback noise. Feedback noise is why Mazda does'nt use a harness ground wire actually.

 

Interesting... I've always hooked my ground to either a bolt or piggy-backed the cigarette lighter's ground wire. Don't have feedback in my ride either.
In my mom's old Ford Probe, sister-car to the mx6 (in case someone reading didn't know), the stereo's ground had to be hooked to ground. Wouldn't turn on till ground was hooked up. It was a JVC. Aftermarket stereos need the ground as they're not all set up to ground through chassis. Guess some are? Curious, what brand stereos have you installed that were fine without ground wire?

 

im going to call some scrap yards and see if i can get a dimer switch to see if i fried it

 

Dimmer switch should be pretty cheap from salvage.
It is possible to test your dimmer switch. Just grab a volt-meter, see if switch is getting power, then check outgoing power. I've never tested one, so i can't give detailed how-to, but it shouldn't be too difficult.
If you don't find the cause of the problem, frying out the new switch may happen.
Good luck!

 

In 1983 the 626 had a feedback problem and Mazda put out a TSB to cut the ground wire for a fix. Ever since then they do not use a ground wire but rather ground through the antenna/chassis.