The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

John H. · 11-09-2007, 12:21 AM

I have a factory GMC wiring diagram book for trucks built after August 12, 1968. I could photocopy the motor/light harnesses and fax you a copy. You could compare them to a chevy diagram where they go into the dash block. If colors and routing are the same, this would answer your question. Why would the dash harness be different? The cluster and interior electrical is the same on the inside.

I will soon find out as I have replaced my dash harness with a reproduction dash harness. I unwrapped my GMC and it was the same. I actually bought a harness without the gauges (cheap on Ebay) and converted it to the gauge style. There are 1 or 2 wires you need to take off the ign to the cluster that provide the lights to light up when you turn your truck on. I think I relocated a couple pins in the cluster plug too.

Good luck.

11-09-2007, 12:21 AM	#8
John H. Registered User Join Date: Oct 2007 Location: Sammamish, WA Posts: 2,115	Re: GMC Wiring Harness I have a factory GMC wiring diagram book for trucks built after August 12, 1968. I could photocopy the motor/light harnesses and fax you a copy. You could compare them to a chevy diagram where they go into the dash block. If colors and routing are the same, this would answer your question. Why would the dash harness be different? The cluster and interior electrical is the same on the inside. I will soon find out as I have replaced my dash harness with a reproduction dash harness. I unwrapped my GMC and it was the same. I actually bought a harness without the gauges (cheap on Ebay) and converted it to the gauge style. There are 1 or 2 wires you need to take off the ign to the cluster that provide the lights to light up when you turn your truck on. I think I relocated a couple pins in the cluster plug too. Good luck.