1978 gauge wiring info

[kglowacky]

just searched the forums to find some help on wiring my gauge cluster with a painless harness. All I am looking for is a picture of the back of my plug and what wires go to what gauges and lights. My plug is a 18 pin factory plug. Two pins have no wires. Anyone have a diagram that I can look at to wire my cluster. Please keep in mind I have no skills to read a factory wiring diagram or lets say limited. LOL A hand drawn 18 wire diagram would do the trick. Seams like all I found on my search was 67-72 Thanks

[VetteVet]

I would refer you to member Hatzie, he has several diagrams of our trucks, and he is always willing to share them.

I have two of the ones you need but I can't seem to get them to enlarge enough to read clearly
I think your missing wires are for the voltmeter but I will take another look.

[kglowacky]

edit

[VetteVet]

ok got oem wiring dia. Unfortunately my wires don't match up with the colors of theirs. I am thinking of hooking up the ground I assume the black wire to 12 volts and then start touching each wire to see which gauge moves. any chance this will hurt any of the gauges?

Hooking up a ground to 12 volts is not a good idea. This would be a direct short.
If you connect power to a gauge on the sender side you may burn up the circuit board.
If you want to test the gauges you have to connect power to the main gauge positive side and then use the sending unit for that gauge by grounding the sending unit. I think a nine volt battery would suffice for the power and you shouldn't be able to put enough amperage through the gauge to damage it. Even then you need to know what you are doing.

Here are the two instrument cluster diagrams of the gauge plug in that I have.









You might be able to save the diagrams to your hard drive and enlarge them there so you could read them.
I only see one open spot on the dash cluster plug. If you can read the legend on the wiring it tells what the wire terminal is for.

[kglowacky]

well after spending all morning on my wiring challenge I think I got ahead of it. My eyes hurt and my magnifying glass was a must and alot of bad words. Here's where I am at. First let me say my pigtail color wires do not match the oem diagram on about 6 of them BUt I think I figured them out. my question is I have 3 pink wires coming out of 3 different pins. I followed them and (looking at the back of the gauge) one goes to the right side of the gas gauge the other two go to the left side of the temp,volt and oil gauge. (one goes to two.) I am assuming these are for ignition power to power the gauges. can someone confirm. I am drawing up a diagram of my setup and will post it once I install and test the gauges. It will be another month probably

one more thing. Not sure how the amp/volt gauge works and since I am not running oem engine wiring not sure what to hook it up to. it has two pins and a plug in pin on the gauge. One is the pink power as I mentioned above