Rich123

My dash lights do not come on when I turn on the headlights. I have rotated the headlight switch in both direction fully.
I need an electrical diagram for a 1978 Vette dash. I looked in my manuals but nada. I looked online but I could not find one.

Can anyone send me one or point me to one.

Thanks
Rich

76CSRvette

papawana I believe has a thread for wiring diagrams. he emails them to you

76CSRvette

found it
http://forums.corvetteforum.com/c3-g...or-anyone.html

Rich123

Great! Thank you. I PM'ed him I hope he is still sending them out.

76CSRvette

he will. he has been doing it for years great guy. I got mine from him in april. I just don't think mine will work for you as these cars vary from year to year very minor but some things are different

0Willcox Corvette

go to the instrument lamps fuse.. with a volt meter.. With the lamp pulled in the on position, test for power on the left side of the fuse. If you have power there then the issue is past the fuse so test the fuse... If the fuse is good, and you don't have power there then more thank likely the issue is the headlamp switch.

The power to this fuse leaves the headlamp switch on the green wire. It goes to the fuse panel and then comes out gray. (to the lamps).

Imho,
Willcox

Cavu2u

Rich,

Did they ever come on? Or was it just an abrupt "Hey! What happened to the instrument lights?" thing?

I like Willcox's approach to the problem.

Steve

0Willcox Corvette

I cheated... lol. I just helped the shop on Friday with the same diagnosis. No power at the left side of the fuse. We replaced the headlamp switch and the problem was solved.

If he has power on and after the fuse, then I would go to the pcb connector behind the speedo and tach. It's common for the fingers on the printed circuit board to come loose and one may not be touching or shorted out. There are instructions here on our site for removing the dash cluster. (also the easiest way to remove/replace the headlamp switch on a 78-82.

Corvette Speedometer and Tach Housing Removal Instructions 1978-1982

Rock-it Man

The instrument dimmer is part of the headlight switch. If it's not a fuse, then it's the switch that needs replacing.

The other option is to hardwire the instrument lights without the dimmer, but then you will have full blast instrument brightness all the time.

Cavu2u

That light switch is kind of a bear to replace, considering it's placement, attached vac tubing & wiring plug, and unique lock "nut".

Steve

Rich123

Hi, guys
Thanks for the responses. I did not get a notice in my email that anyone had responded past the first couple. I was working on other things and had not gotten back to the dash light thing yet but when I do I'll make sure I post a the results.

Rich123

Thanks for the link, that was probably going to be my next question...."how do I get the dash out"...was not looking forward to that.

Tooonz

I'm going to be visiting this issue very shortly

jbaron

I've got a somewhat similar issue. The fuse for the dash lights has been blowing out. Ideas?

Cavu2u

A short to ground. Can't be specific unfortunately, as it could be almost anywhere in that circuit where Ground runs in the chassis. One good thing about a fiberglass car; it narrows the search a bit for a short to ground.

I don't recommend wrapping a fuse in tin foil, insert it in the fuse box, and then look for the place where the origin of the fire started.

Steve

Rich123

I finally got to look at the dash lights problem again. Under the dash on the drivers side next to the fender is a fuse block. In that block is a fuse labeled "gauges", it's right above the "radio" fuse. I assumed that this is for the "gauge" lights. I spent all my time reading 12v on it when I turned on the ignition key etc, etc, etc, I wasted my time.
I finally looked at the bottom of the block an saw one called "inst lps", in printing so dim I had not noticed it before. It was blown......they work now.
By the way, I did not have a fuse that was physically that small and I did not want to go to the auto parts store and buy a little fuse. I noticed that the plug-in fuses I had with spade connectors have the same pitch (width) as the little fuse. So I bent the prongs back to be flush with the body of the little guy and stuck it in there...wala, I have dash lights.

Thank you for all the advice and help, I learned a bunch about my Vette.

Tooonz

Rich123 thanks for the follow up, it lead me to investigate our fuse panel a little closer, I found ours to be top left on the block, and it did NOT have a fuse. Put one in and lights all work This forum rocks.

Rich123

Isn't it nice to be able to drive at night without a flashlight to see the gauges and a GPS to see how fast you're going.