Just got a 1978 CJ7 that I love, but as I'm slowly working out her kinks, the wiring has got me.... lost.
Spent the last 4 hours or so backtracking, deleting back wiring done for the sound system, etc. As of right now, I still cannot figure out why the dash lights do not work.
A few bulbs do work, though the rest were left absent from the PO. I have not replaced the light switch, though I 'jumped' from the hot to the dash lights in the light switch block and nothing happened. Just for fun I tried the headlights via the same method, and they work. So it's something dedicated to the dash lights.
edit: I tried replacing the fuse (used a 5amp instead of 3, but it should be a-ok). No help there.
I have tried backtracking the ground, I hear this is the most common solution. All of the dash lights are single orange wires, and I cannot figure where on earth the ground comes from.
In wiring diagrams, I do see that the ground links up to a degree with the lights for the a/c, etc. but no place that it directly links up with the dash lights themsleves. What am I missing here??
I know a lot of people have just "added" ground, but where on earth in the chain would I do this??
You can just run a temporary wire from the neg terminal of your battery and connect the other end to any bolt on your dash. If the lights then work, you know you have a bad ground and you can then run a NEW permanent ground to your dash. If they don't work, then you might want to see if you are getting 12V of power through your "orange" wires that go to your dash lights. Also, make sure that your "dash light dimmer" switch is not scrolled down in the full dim position.
I just went through almost the same thing with my 79 I removed the headlight switch and sprayed it with electrical cleaner. that fixed my problem but it does not seem to be yours as some of them work. I believe each individual light gets it's ground through the gauge it's mounted in. so maybe by pulling each and using a little sand paper in the mounting hole you'll reestablish your grounds again. It's worth a try. John
John in Michigan (Back in Horseheads NY) '79 CJ7, 2012 Chevy Malibu. 07 Nitro,
Here's a diagram that may help you along. Some of the dash lights have their own ground, some ground to the gauge.
There are also other orange wires that aren't for the lights. One comes off of the switch and goes to a dome light of some sorts. Another goes to the 4wd light.
78 CJ7.. 258.. TH400/Dana18.. SOA/stock YJ springs.. 35" General Grabbers.. Waggy 44s.. 4.88 gears...Spartan/Lockright...Fiberglass front to rear
Fairly confident it is NOT the ground. Tried replacing it, no luck.
I checked at the fuse panel, and without a fuse I am able to get 12v terminal to terminal with the lights engaged. So that checks out.
Unfortunately, when I then go check the individual lights, I maybe get 0.02v. So something is not hooked up right, though for the life of me I can't figure it out since so much of the wiring is bound together (factory I assume). Could it be something on the other side of the fuse panel that I don't see??