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Dash Lights Out

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Old 06-29-2004, 05:18 PM
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Default Dash Lights Out

I know, look at the fuse. It was blown, I replaced it and it blew again. So, I took apart the dash (what I could of it) and found a loosened wire behind the CD player (oops, that would be my fault). So I fixed that, and threw in another fuse. That fuse is still good. The lights affected are all the gauges and the HVAC control and the outline of the car in the "status box" thingy. Now they are all still out, but do come on when the dimmer switch is used to turn all the interior lights on. So, I believe that the bulbs are still good, the fuse is fine, but the dimmer switch is maybe messed up? All the status lights still work (like "brake" and "check gauges").

Any ideas or similar experiences?

Subquestion: How do you get the **** off of the dimmer switch so that the upper dash panel (the black and grey piece that goes from the cigerette lighter to light dimme/sentinel controller, at least in the '97) can slide off and I can get to the switch.

Off topic question: While playing with the HVAC ***** I tried to figure out why the highest speed setting doesn't work (fan turns off at all the way right and left), the switch is good, I tested all the settings. I put it back together without messing with anything and highest speed worked...once, still broken I guess.
Old 06-29-2004, 08:17 PM
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With the manual systems, I believe there is a high speed relay involved. To get the **** off from the lights, you have to poke that metal tab behind the **** towards you.
Old 06-29-2004, 08:56 PM
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hehehe, I knew I read something about this before, forgot to check the techinfo before posting... Bad rheostat in the dimmer switch. I'll go check that out
Old 07-07-2004, 11:56 AM
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Originally Posted by jonboll
hehehe, I knew I read something about this before, forgot to check the techinfo before posting... Bad rheostat in the dimmer switch. I'll go check that out
Agreed. As for the high-speed relay, it'll be somewhere under the hood near the blower.

I have to do this from memory since this was the usual fix for the problem on older GM cars, and my car has the electronic system so I can't look at that one for specifics, but here goes (and maybe we should have a TechIno article on this):

On older GM cars, if the high speed blower setting quits, but the other (lower) speeds still work, the problem is most likely in the circuit for the high-speed bypass relay under the hood. This relay allows full power to the blower motor without running the risk of melting the dashboard switch. However, the massive current flow, especially as the blower motor ages, tends to melt an in-line wiring harness connector, and the high-speed relay eventually won't get enough power any more. It will click just fine when you move the dash switch, and you can sometimes even measure voltage on the fat red wire leading to it, but it no longer provides enough current flow to drive the blower.

The fix in such cases is to follow the fat (10-gauge) red supply wire back from the relay towards the engine. (The relay itself has a four-conductor plug, two fat wires and two thin ones, and is mounted on the firewall or a bracket hung off the evaporator housing, in the vicinity of the right (passenger'*) side hood hinge.) You will find a plastic in-line wiring harness connector, possibly with two or three other wires included. Pry open the connector and you may find that the 10-gauge contacts have melted. The other wire connectors are probably fine, so reassemble the connector, solder in a bypass connection around it for the 10-gauge circuit, and you should have your high-speed blower back again.
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