Dimmer Switch Short?
 

Bonnie manages to keep my life exciting, to say the least.

Now that DST has kicked in, it's dark by the time I head back from work. So all week it's been no problem. Today I looked down and noticed the dash was a little dim, so I thought I just needed to rotate the dimmer switch. When I turned it, the IP turned all the way off and depending on the rotation of it, little by little, would turn on full, dim, or not at all.

So the real problem was this appears to be a major short. My voltmeter, which has finally been steady for the past 3 months, started bouncing severely. From about 10 V to 14 V. I was afraid it was going to shut off on me. Would this short really be significant enough to cause that much voltage drop? I would expect a fuse to blow if that were the case.

How hard is this repair? Anyone have the part number I need?

Try checking the battery cables first. A loose cable, or corrosion can cause weird things. It caused my interior lights and chime to act very weird when my cable was loose/corroded.

Yes I was thinking that also, I've cleaned the cables/connections within the past few months (and seem to have my battery out every weekend for various projects) and the positive cable is only a few months old. I will double check make sure connections are tight, but I'm pretty sure this is a headlight/dimmer switch problem.

They could be independent, but there is definitely something wrong with the switch. From my research it looks like this is a pretty common issue on the 94. I'm just surprised at the voltage spikes.

Do you have a multimeter? If you do, and your voltmeter on your dash is fluctuating like that, check your battery to see if its actually the battery, or in the IP. When looking for corrosion, you should check under the boot on the cables at the battery too. I wouldn't be surprised if some corrosion got under there.

I'm thinking this could be two separate issues. I can't really see a short in the dimmer switch causing the fluctuation on your voltmeter, but it may very well be causing it. Are any of your other gauges acting weird? They could have a common ground thats dirty, or broken.

Today was the first time I'd seen it fluctuating in quite some time, and like I said, it started immediately after touching the headlight switch. I'm positive there is no corrosion on the cables. I've used a wire brush on the battery and cables. Alternator and starter are both recent. Main ground is clean. If I can get it to fluctuate while idling I'll try and measure the voltage, but right now I have my dimmer switch in the "sweet spot" and prefer not to touch it until I have a replacement :) The drive to work tomorrow (lights won't be on) may tell us more.

My oil pressure gauge has been a little bouncy, but I think that is a separate issue. It wasn't doing it while the meter was fluctuating. I have a small oil leak out the pan and a dirty oil pressure sensor, so I'm not thinking it's the gauges. All others have been fine.

Also, the brightness of the headlights/instrument cluster was fluctuating with the changes shown on the meter, so I believe it was an accurate reading.

Hmm. That does make it sound like your dimmer switch. I don't blame you for not wanting to mess with it too much when you found the "sweet spot" haha. Getting a used one from a j/y could be a hit or miss too. You might find 3, and all of them have the same problem..

Yeah that's my thought. My brights are already rigged to a big red switch below my radio. Don't be surprised if there is another switch next to it soon...

I'm looking at this thread:

https://www.gmforum.com/showthread.p...light=rheostat

It sounds like I just need a new headlight switch. However, Autozone doesn't appear to sell one compatible with automatic lights.

http://www.autozone.com/autozone/par...mString=search

Can anyone help me out with a part number? It sounds like the 96+ have better switches. Would this work in mine?

http://www.ebay.com/itm/1998-Bonnevi...item3ca980ccf0

Thanks for the help.

What if you just disabled your automatic lights? I wonder if that would work with that switch..

Not sure, they really need to label connections or something on a diagram. I'd prefer to keep automatic if possible though