[Oldgreentruck]

Hi. I’m new here and buying my first gmc. I’ve had numerous 48-55 chevys. I am looking for a complete wire harness for a 55 gmc 2nd series 100 short bed. It has the Pontiac 287 and Hydramatic trans. Can I use the Chevy harness? Thank you.

[Bill Hanlon]

I know of at least one difference with the Chevy harness. Chevy has both left and right turn signal indicators in the dash while GMC just has one lamp covering both left and right turns. The Chevy harness won't have a wire for the GMC HydraMatic shifter position lamp.

[Oldgreentruck]

Thank you for your prompt reply. The Chevy harness for an 8 cylinder is the only one I can find. So I’ll have to modify it to work. Again, thank you. Dennis

[Bill Hanlon]

The turn signal indicator is easy to fix if you use a flasher marked DOT 550. Connect the one GMC indicator to the "P" (pilot) connector on the flasher. The P connector is the one in the middle.

[Stuart]

Originally Posted by Bill Hanlon

I know of at least one difference with the Chevy harness. Chevy has both left and right turn signal indicators in the dash while GMC just has one lamp covering both left and right turns. The Chevy harness won't have a wire for the GMC HydraMatic shifter position lamp.

Chevy trucks were available with a Hydramatic transmission too, so wouldn't their harness have the wire for the shifter position lamp as well?

[Bill Hanlon]

The Chevy truck HydraMatic shifter didn't have the fancy box that the GMC had for indicating which position the shift lever was in. The GMC lamp was in the box. I'm not positive the Chevy did not have a lamp, but I don't think it did.

Here is the Chevy indicator: https://chevy.oldcarmanualproject.co...r/57tom021.htm