Hi all I'm new to posting to a forum I look for advice from them but this is the first one I've joined

I bought an 87 Firebird Formula back in March this year my 2nd one I had one back in 93 (silly me I sold it)
and been putting it back together and working out some bugs
electrical is not my strong suit and trying to understand it more

I am having trouble with my dash lights working (they don't)
I had trouble with the parking lights and a friend did a bypass on the front parking lights (brown wire) and now they all work

but after looking at the wiring diagrams for hours and trying different things I still can't get them to work

today I changed the remote dimmer and I was optimistic but no go
I also pulled the dash and changed all the lights to LED and they work with power to terminals 2 and 3
my key chime works now though

if there is anyone out there that can help me I would be grateful

 

IIRC the Firebirds have a "dimmer module". It's kinda Stone Age in a way; an analog (linear) regulator. It has a particular part, an old, very familiar transistor. Its JEDEC part # is 2N3055.

Discrete Semiconductor Products | Transistors - Bipolar (BJT) - Single | DigiKey

Seems like from what I hear, (I've never had a Firebird) this is what goes bad. I'd recommend the NTE one. It's expensive I know, but worth it. Might want to buy more than one, just in case, if you can afford it.

Use heat sink compound, like you can get at the computer store, when you install it. It may come with an insulator, which would be a thin sheet of mica: you MUST use it if this thing has one (I don't know offhand but it probably does). Clean it off carefully, both itself and the heat sink it mounts to, with lacquer thinner, before assembling it.

 

yes its called a remote dimmer and as I said in my post I changed that today
but wasn't the problem
but thanks for your response

 

First thing first: find and fix whatever was the problem with your Parking Lights rather than bypassing the problem !!

Second: Do you have this problem if the LEDs are removed and regular bulbs are installed ??

Third: Here is a schematic from the 88 shop manual for the analog cluster backlighting:



( install regular bulbs and test before you start probing !! )

If everything else that gets a GREY wire in this schematic has proper backlighting than the issue is isolated to the cluster. With the HEAD or PARK lights on: probe the cluster C1 plug terminal #3 and cluster plug C2 terminal # 3 ( both are GREY wires) for voltage. Also probe C1 plug terminal #2 and cluster plug C2 terminal # 2 ( both are BLACK wires) for ground. If these circuits have voltage/ground when the HEAD and PARK lights are active than the problem is probably the cluster printed circuit. If these wires do not show voltage/ground than trace the wiring to find the short ----> or just splice a "jumper' wire from one of the other GREY circuits shown in the schematic ( At radio, HVAC controller, shift bezel bulb, ect.. ) to the GREY cluster wires ( C1 plug terminal #3 and cluster plug C2 terminal # 3).

** a defective "AUDIO CHIME" can cause weird things to happen. You might hear the chime now, but it could still be defective. If you have a spare - try to swap it for the one currently installed and re-test for backlighting function.

 

I posted about the transistor because they fail pretty often; you may have put a bad one in.

As Drew's schematic shows, the dash lights are actually on the tail light circuit, which of course is also the parking lights when applied to the front of the car. Powered from the same contact of the headlight switch.

I don't know, and can't begin to guess, what is meant by "bypassing" the parking lights. Do the tail lights work? If not, then you're right, the dimmer transistor might not be the problem. Instead you need to investigate the tail light circuit. Fuse, headlight switch, & wiring.

 

So the bypassing was simply cutting out the area of the wire where we found to be the possible short
and so after doing a continuity test on the dark green wire and the brown wires going to the remote dimmer there was continuity in them to ground (thats never good)
I decided to do a bypass on those and everything works now I wasn't able to find the shorts in my wiring but they are no longer a problem

and btw the new remote dimmer went back to autozone it was defective I'm using the old one

Thanks for posting your thoughts it helped me think this through a little more