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Discussion Starter · #1 ·
Ridiculous, I know. Sometimes my dash lights come on by themselves, other times they stay dark until I smack the top of the dash in the center above the little display. I hit bumps, and the dash lights often go out... I smack the dash top and they go back on..

How is this possible? If i had a short somewhere... I wouldn't be able to smack the dash top and get them to come back on.. what harness or plug could have come loose that is doing this? Anybody else ever have this crazy problem?
 

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Since the SID controls the lamp intensity (little round clear sensor on the left) and the Blank Screen button turns off all the lights except the speedometer, I would start there. If you had a friend that would swap SIDs you could tell a lot... Ron
 

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Discussion Starter · #4 ·
Smacking dash over SID turns lights back on, but occasionally rolling the dimmer up and down quickly sees to work also, or may be coincidence.

Is there anyway to bypass this and keep the dash lights on all the time.. I'd prefer that anyway.
 

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I have never seen a sid fail in this manner, but I have had my dimmer switch go.

Completely remove the sid and see what happens. If you get the radio out you can use your hand to pop out the sid. Then the plug is easy to undo.
 

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Discussion Starter · #6 ·
i'm a little crispy fried from working in the hot sun the past couple days.. to clarify..

If i remove my SID unit in the dark and the lights remain on, or turn back on... the SID unit sensor is faulty..

If I remove the SID unit and the lights do not come on, the dimmer roll switch is toast right?
 

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I doubt the lights would work at all without the sid plugged in, so not likely to help much.
From an electronics perspective it's most likely a connector somewhere along the line, second most likely is the dimmer control (it's a potentiometer) these things can get crackly with age - although a dodgy pot will usually come on and off as you turn/adjust it, which isn't your problem by the sound of it.

Probably a bad connector and/or bad earthing connection. Pull the covers off and wiggle wires until you find one that triggers the lights, and then unplug and replug any connector nearby, and unscrew, wiggle and re-tighten any nearby earthing points. A squirt of contact cleaner in the connector wouldn't hurt but chances are just the act of replugging it in will scrape the terminals and make it work fine for another few years.

Andrew
 

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Maybe I should have been a little clearer. The SID controls the brightness of the instrument cluster, the ACC or MCC, the radio and itself. If all are going dim or bright, it could be the SID. If all but the speedometer are out, it could be the Blank botton on the SID. If only the lights on the instrument cluster are going out, it could be a crack on the printed wiring board on the cluster. I had a cluster where the speedometer and turbo guage would work if you hit a bump in the road. Then finally as others have said, it could be the dimmer switch on the left side of the dash. And it's going to be hard to trouble shoot without having spares to change... Ron
 

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I would bet you need a new rheostat ( dimmer switch)
This is not all that uncommon on these cars.

You can get one cheap on ebay usually under $25
 
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