Need instrument cluster help!!
 

I need some help with the wiring plug on the tach dash I got for my Blazer. I have a 77, and have a 79 cluster. I have a mechanical gauge to fit the hole, so that is not a big convern. My question is about the wiring for the main cluster plug. Does anyone have a diagram for the plug, so I can repin what I have and make it work? I have the tach wiring figured out, just need help with the main plug. Thanks in advance!

I just traced the circuits on the old dash, then for the new one. Move the wires for fuel sender from the old position to the new, then temp, etc.... Just draw a diagram of the connector, labeling with colors and circuit function, then move the wires to the correct position for the new dash. Good luck!!

I was going to do that, but I am lazy. Looks like that may be next week's project.

BIG TIME MAJOR ELECTRICAL CHANGE FOR 78.

78 was the first year for the blade style fuse box. Oil presure went electric that year, gas door added, rear seat foot well and fold and tumble rear seat first year as well. LOTs of firsts. Your going to have to trace down the harnesses. Best place to start is your local library and see if the have the year spicific repair manuals on Microfisch. It's 10 cents a copy at mine.

Check a Haynes Manual for the trucks. That is what I use.

Ok, I got the main plug wired, and eerything seems to work. Next question: where do I hook up the power lead for the tach? I put it to 12V switched power on the fuse box, and the tach needle swung 360 degrees. What did I do wrong there? I ran a wire from the "tach" port on the distributor cap, and grounded the black wire to the body.

Does it work with the engine running? If not sounds like the tach needs to be fixed. Do you have any other ignition system besides stock? (MSD etc..)

No, it's an HEI. I was thinking maybe my ground is not the best. I am going to try to fix that, and see what happens.

Jonboy,

Any progress with your tach? I just bought an '82 and the factory tach does the same thing. I measured the lead labled "12v" on the instrument cluster on the tach connector and there was nothing there, 0v. So I jumped 12v to it and the needle just swung all the way to max. I traced the wire (pink on my truck) all the way back to the fuse box and it is 0v there to. All the fuses are good. Can't figure this out.

I haven't done anything to it yet. I tried to put the stereo in all weekend, and ended up doing everything else but that. I just left it unhooked for the time being.