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OK, here's a good one for you guys to figure out. My speedo/tach lights stopped working. After tracing, I've come up with the following. If I disconnect the wiring from the dimmer (rheostat)and connect them together, the lights come on. This led me to believe that the dimmer had gone bad. I checked it with the multimeter and it checks out OK. I hooked up a bulb to the dimmer and it works fine. Put it back in the car and same problem, speedo/tach lights don't work. I've even tried a spare dimmer switch that I have and it doesn't work. Any suggestions? Thanks in advance
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Check to make sure the light socket that holds the bulbs is grounding to the receptacles on the guages themselves when pushed in.

Weird set up, I had the same problem myself and found it to be the grounding of the light socket when pushed into the gauge receptacles.
Full contact was the problem on mine.


quote:
Originally posted by 4NFORD:
OK, here's a good one for you guys to figure out. My speedo/tach lights stopped working. After tracing, I've come up with the following. If I disconnect the wiring from the dimmer (rheostat)and connect them together, the lights come on. This led me to believe that the dimmer had gone bad. I checked it with the multimeter and it checks out OK. I hooked up a bulb to the dimmer and it works fine. Put it back in the car and same problem, speedo/tach lights don't work. I've even tried a spare dimmer switch that I have and it doesn't work. Any suggestions? Thanks in advance
I had a dask light problem show up last night while driving home and I found that the knob and shaft onthe rheostat itself is "loose". Turning the knob did nothing but wiggling it back and forth got my dash lights to come on and go out. The shaft bieng loose was not obvious and i found it by accident. I think the first chance i get i plan on bypasssing the rehostat all together. Too much lighting on the gauges has never been my problem.
If it was a rheostat problem, wouldn't it be effecting all the lighted gauges and not just the speedo & tach ?

quote:
Originally posted by 4NFORD:
It works when I bypass the dimmer rheostat. If it were a grounding problem wouldn't it not work regardless if the rheostat was connected or bypassed until the ground problem was resolved?
Not so. They run on different rheostats (the speedo/tach is under the left dash and the gauge panel rheostat is on the console. My gauge and all other lighting works. I have bypassed the wires from the rheostat and all works well. It is not a grounding problem or the lights would not worked even when the rheostat is bypassed. Since the rheostat switch works when tested, the only thing that I can think of is that the circuit is not sending enough power through the rheostat itself. I'll have to get the volt meter out and check.
Mine all run on the same rheostat on the center console. Maybe you should try running them all through one.

quote:
Originally posted by 4NFORD:
Not so. They run on different rheostats (the speedo/tach is under the left dash and the gauge panel rheostat is on the console. My gauge and all other lighting works. I have bypassed the wires from the rheostat and all works well. It is not a grounding problem or the lights would not worked even when the rheostat is bypassed. Since the rheostat switch works when tested, the only thing that I can think of is that the circuit is not sending enough power through the rheostat itself. I'll have to get the volt meter out and check.
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