Color Wiring Diagram FINISHED

[70gmc4d]

Originally Posted by chuchito

I have a 1972 GMC suburban, and the wiring is driving me crazy. The diagrams I found on here look similar to what I see under the hood but not exactly. Also, I don't see the blue wire that is supposed to be to the oil pressure on my harness but my guage cluster does have a oil pressure guage. The engine harness actually only has 5 wires. I unplugged it and looked at the female plug on the firewall and it also only has 5 inserts. The five wires I have are the tan, dark green, purple,pink, and brown with white. Can someone chime in?

My 70 GMC has a mechanical oil pressure gauge that is plumbed in the block next to the distributor. And the 70 gmc has 4 headlights up front.