Hi all, just got myself a 1980 vette and noticed that the dash lights do not come on with the lights switch pulled. Lights blinkers etc. work fine, is as simple as a fuse or more intense.any help will be appreciated.
Also does anyone have a link to show the original fuse panel, mine is worn and cant tell what fuse gos to what. It has the plastic head fuse and not the old glass tubes.
Thanks
Robert

 

You should get a shop manual and AIM if you're going to do your own work.

 

It could be a fuse, light switch, or printed circuit in back of the gauges, make sure the big plug is in all the way behind the dash , Ron

 

On my '74 when I first got her it had no dash lights....it was the headlight switch...

 

I am CERTAIN that you checked this:
when you pull the headlight switch OUT, you also turned the switch **** counter clockwise to BRIGHTEN the intensity of the dash lights, right ? Turning it CCW to the STOP will illuminate the interior lights.

 

Welcome to the Forum!

As already stated, if you plan to work on your car, get a real GM Shop Manual SPECIFIC for YOUR year car. The generic "C3" 1968-1982 shop manuals will not be as useful to you. Most of the large parts Corvette Forum vendors carry reproduction manuals. Section "8" of the shop manual covers electrical. Also very useful are wiring diagrams, again, get one SPECIFIC for your year car. Many vendors also have these, and reproductions are also available from NCRS.

The A.I.M. (Assembly Instruction Manual) is the guidance the factory workers used when your car was assembled in St. Louis. These are also available from Forum vendors - again, get one SPECIFIC for your year car.

Now until those are available:

Reference the post by Avette4me that contains the diagram of the fuse panel. The 7.5 amp fuse (panel top row left center) "INST LPS" is for the Instrument Panel Lamps. Check this fuse.

Check for voltage at the Light Switch (Circuit 44) it is a dark green wire.

Check the connection at the Instrument Panel.

Check the bulbs, they may be just burned out.

Check the bulb socket for broken wires and loose connections.

Sometimes, it is easier working under the dash if you take the seat out - four bolts.

Hope this helps. Again, welcome to the Forum.

 

Robert, I just repaired my dash lights on an 80, I started with the 7.5 amp fuse, it was blown, replaced it and it blew as soon as I put the lights on. The next thing that I replaced was the head light switch and that solved the problem. It will be a lot easer if you take the driver sest out. Ther are complete instructions on replacement the head light switch in the 1980 Shop Manual It will be your best friend when your vet needs work!!!!

Good luck Joe.

 

Hey Ron,
I have a 1980. Replaced light switch and all the bulbs on dash.my r/turn signal is not working. Swapped bulb holder out and still not working. I have a repair manual and electical diagram and both are no help. 1) can the thin copper tape at bulb openings be glued if loose. 2) is the position of each bulb diagramed anywhere? I may have put 1 in the wrong opening. There were 3 without bulb holders in them. Both turn signals worked before i started replacing all.
Thanks Frank

 

Its very possible the dash light ceramic rheostat on your headlight switch has failed because mine just did a few days ago. When the rheostat fails the dash lights won't come on because the circuit is open.

 

Multiple problems in the circuit are certainly possible and likely related.

For instance in my '79 my IP lights did not work at all. Fuse blown. Fuse replaced but still no lights. Found that the rheostat in the headlight switch had burned through. Replaced the switch and things seemed OK for a while. Then the fuse would blow when driving--fine when parked. In found that the printed circuits behind both the speedo cluster and gauge pack had delaminated allowing the traces to momentarily short to one another when the vehicle was moving. I was able to repair the printed circuit for the speedo cluster but had to buy a replacement for the gauge pack as there were other problems in it as well. I suspect that the occasional short in the printed circuits got progressively worse and eventually caused the rheostat in the headlamp switch to burn out.

 

It is a brand new light switch. I have not installed it in the dash yet cause the dash is out. I am replacing it also. The circuit board does appear to have some copper contact tape loose in areas, guess i need to order a new one.can the copper contact tape be super glued back in place?
Frank

 

Yes. That's what I did with mine. It seems to be working fine on the speedo cluster printed circuit but it has only been a few months

Compared to earlier C-3s (before '76) I believe we're lucky in that both the speedo cluster and gauge pack are relatively easy to remove.

The printed circuits aren't particularly expensive but if your experience is similar to mine (and I believe that of everyone else) those "not particularly expensive" things become $$$s very fast and $,$$$s surprisingly quickly even for a low mileage "survivor" in very good shape.

I will also say that the replacement printed circuits [appear] to me to be superior to the originals. Rare as many replacements I've purchased are VASTLY INFERIOR. I could nearly shoot myself for not ordering OEM headlight actuators when they were available about a year ago. I cheaped out to find two failing within 3-4 operations and can only pray that mine will last for a few years of very occasional use.

 

Mike,
Thanks for the reply. I think i am going to order a new board. I just bought a new light switch and now people are saying if the old board has a short in it it can blow the rheostat on the light switch. Great!!! Hope it has not already. My dash is still out so want to make certain all is ok before i put it back in. The board is 59.95 plus shipping but as you say .... I bought the fixer upper in may and have already dumped 4900 into it not including the paint job i am having done now. Hope it is worth it.the dashpots and lights were all new in 2012 so hopefully they will be ok.
Thanks,
Frank

 

Unless you read it elsewhere as well, it is my supposition that the burned out rheostat is the result of a delaminated printed circuit. Coincidence of problems found among neophyte 78+ C3 owners does not mean that my diagnosis is correct.

 

Have you checked your fuses.....mainly the taillight fuse...and the INST LMPS fuse.

If you printed circuit boards looks good and no breaks.,..I doubt that it the problem.

You wiring diagram is your BEST FRIEND in this type of problem. And if electrical repairs scare you...or you do not understand what you need to look for....ASK. Your cars electrical system is quite simple once you understand how 'things' work. SO...if you know how to use a road map....then using wiring diagram is NOT that much different.

If you want 'one on one' help over the phone. PM me and I will give you my shop phone number so I can walk you through what to test and check....BUT...you will need to have you wiring diagram handy so you can 'see' what and why 'things are being checked. The choice is yours.

And for what it is worth....I have had brand new headlight switches that were bad in the circuit for the instrument lights......just 'saying'. This is EASY to verify.

Oh yeah....you will need to at least have a volt/ohm meter.

DUB

 

Frank-

The laminated pcb can't burn out the rheostat.... the board is the weak link in the circuit and will blow first... sometimes faster than the fuse. If the board is blown, I highly suggest you find the source of the problem before you install and cook a new one.

If you have the cluster out of the car, and sitting on your lap, the ground is the first wire down (left side in the picture) and the power wire is the forth wire down from the top(right hand side in picture) now this is sitting on your lap so in the dash it would be reversed. Check there and also check the fingers where they connector goes in.... they are famous for coming de-laminated and touching another one.

IMHO,

Willcox

 

I superglued down many delaminated lines on my printed circuit when redoing my '80 dash (especially the fingers at the connection point). If I had known that replacement printed circuits were as good or better than original I would have just replaced them. I've just gotten into the habit of reusing as much as possible rather than buying repro...