speedometer pinout for 91 c1500

[black91_6.0]

well guys i need some help, where can i find the speedo pinout i my 91 c1500 so i can get my original cluster to work

[LS1GMCTruck]

You need the speedo pinout for your 6.0 litre engines computer? Or the wire color & location for the speedo wire coming out of your drivers side firewall? Or both?

[keniff]

im assuming the firewall side
an if not I DO so please tell me lol
i have a green wire i cant find what it goes to...plus i have the speed sensor for the tailshaft of the 60E i though is what i needed but i think im wrong

[LS1GMCTruck]

im assuming the firewall side
an if not I DO so please tell me lol
i have a green wire i cant find what it goes to...plus i have the speed sensor for the tailshaft of the 60E i though is what i needed but i think im wrong

The VSS signal wires come from the trannys tailstock, go TO the computer, THEN to the drivers firewall speedo wire. There are a few different green wires that come from the computer, with different purposes. Different year OBS trucks, have different wire arrangements & colors coming out of the firewall. You have to get the same diagram as I mentioned above, "specific" to your year truck, to find ANY of the dash wire functions.

[black91_6.0]

no i have the one for the pcm i need info on where to tap into so my original speedometer can work

[LS1GMCTruck]

no i have the one for the pcm i need info on where to tap into so my original speedometer can work

Can't help you then. Maybe RedHeartBeat on here can though. You need the firewall outlet wire diagragm, specific to your year truck('91). All the wire function locations, and each specific wire color, is on that picture diagrahm. Its a great diagrahm to have for future use as well. It just might be available in one of those auto store, Chilton type repair books. Or do a Google search for it.

[92 6.0]

I don't remember exactly what year they went to the drac box being behind the glove box but that's where I spliced in for my speedo and cruise.

[black91_6.0]

okay thanks ill look it up in alldata