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Digital Cluster!!

13631 Views 60 Replies 22 Participants Last post by  schofell84
My digital cluster in my 94 caprice works when the headlight switch is off but when i turn the headlight switch on it goes out anybody ever had that problem or is it my wiring going bad?
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no the whole cluster blacks out when you turn the lights on
so what about the lights on your A/C controls? There are alot of things on the dash that light up besides the cluster when the lights are on!
no the A/C controls dont light up either
The only thing that I can think of that will make things happen the way you are describing is for the dimmer (little wheel to the left of light switch) to either be all the way in the dim position or faulty or a possible wiring issue. If you roll the wheel all the way up does the dome light come on?

If you remove the fuse #42 (Int Dim 10a) the digital part of the cluster should light up bright with the lights on just like it would with the lights off! But check that fuse to make sure it's good! It controls all of the dash lights!

Have you tried unplugging the stealth switch? With it unplugged it works just like the cars the don't have it! Could possibly be a short there!
im in on this since the same issue is goin on with my non 9c1. With mine, dimmer has been replaced, dome comes on when rolled up, fuse is good, i pulled my fuse just so i can at least see my speed since i work and drive at night. I even replaced the little dimmer module thing mounted down under left of the steering column. I have no clue where to look from here. Frustrating as hell, and my thread about this same problem gave me no solution other than the dimmer switch. Im just witing for that one dude to chime in that had and fixed a problem like this othr than the dimmer.
Did you replace the dimmer with a new one or a used one? Seems the problem is either power isn't going into the dimmer or it's not coming out of it!

Do you have access to a Volt Meter or a test light?
a used one, I bought one here and was told it was good ( dont have anyone here with a new one to try out)
I have a multimeter... ashamed to admit that I have no idea how to use itcwm3 I can handle detailed instructions tho... ;)
ok I was finally able to duplicate exactly what you guys are describing!

There are 4 wires going into the dimmer switch. The yellow wire on top is the feed from the light switch and should measure around 12v when the lights are on! If you aren't getting the voltage on that wire with the lights on then you have a wiring issue somewhere between the light switch and the dimmer switch. If the voltage is good there the next wire to check is the Green wire on the bottom of the dimmer. This is the feed for all the dash lights. The voltage at this wire will be somewhere between 6 - 12 volts depending on where the dimmer wheel is in it's range with the light switch on. The wirring connector must be connected to the dimmer wheel to get voltage to the green wire! If you have voltage there then you have a wiring isssue after the dimmer wheel!! If that's the case you need to make sure the ground side of the lighting circuit is actually grounded!

Good luck guys I hope this helps!!

If you need help with the voltmeter Google it :)
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ok thanks man ill check this out
good info, thanks!
now on to google lol...
if you guys are getting power on the yellow wire to the switch but not to the green wire the dimmer wheel is bad! Remember it has to be plugged in to the switch :) the other 2 wires work the interior lamps! I also noticed when the switch was unplugged the chime wasn't working for when you leave the lights on but as soon as I plugged the dimmer back in she started chiming again!

You can also unplug the switch and use a jumper wire from the yellow wire to the green wire to see if they come on! that would be a quick way to see if it's the switch! if they don't come on then strt testing for power :)
Try this... wait for a really hot day, turn the heat on blast, then park in the sun. Might need to be warmed up. If that doesn't work turn the a/c on and you'll be so glad to get cooled off that you won't even care about the lights!
Well thanks for the usless post!

So did either of you guys find out anything on your situations? Let me know if you need any further help!
I appreciate all your advice and help man^^^
I havent had a chance to tap into it yetcwm3, been too busy finishing the window channel and dash on my skylark so I can get that windshield back in. Im gonna try to get to it this week, if i can figure out how to set and use this Multimeter LOL! (sad i kno)
i can wrench all day long but when it comes to electrical... uh... derr de derrr
BUMP!! Has anyone had this problem with thier caprice?
Well if you guys have checked everything around the light switch the transistor, the little box on the side of the column support, and power and all that, it could be something in the line that powers the lights up that is shorted, i.e. start unplugging all of the components that are attached to the light dim output of the transistor module. Looking in my FSM I would start by getting the lower dash off, this will cause you to unplug the ashtray light which is one attached to this, see if it lights up, if not carry on to the next which would be the HVAC controls, check again still doesn't work, unplug the radio, check again, still doesn't work, unplug the english/metric switch and the light off button if you have one, check again, still doesn't work then take the cluster out and plug in all the other stuff that you unplugged previously, do they work now, then it is the cluster. That is all that I can add, big pain in the ass to do, but I think that is all that you are left with.

Oh one other thing that is attached to this circuit is the audible warning box, located in the convience center under the dash on the firewall, should be a green box, unplug that as well. Hope this helps.
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thats good info. thanks!
been too busy to even think about messin with it. but i will try this out.
Back from the dead

Did anybody ever figure this out and get it fixed. This just happened to my SS last night. I had had a few beers last night and was driving home (right down the street) and suddenly I was like "Whoa , why the hell is it so dark in here"? Well duh my freaking dash lights were'nt on. I've never had a single problem from digi dash before, not even a flicker.
So it would be greatly appreciated if somebody has any info on this that they could share.
If just your cluster is out, (Totally not when you have the headlights on as was the beginning question in this thread) then this may help you. (About 1/2 way down the page)
My cluster is doing what the OP's was doing. Everything lights up perfectly fine with the headlights off. When you turn the headlights on the cluster blacks out.
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