1972 Blazer Underhood Wiring
 

I'm trying to get the wiring reinstalled in the 72 Blazer build that I'm working on. A PO had molested all the wiring harnesses. I also have a 71 GMC K1500 that I refer to since both the truck and Blazer have 350/350 with AC.
My 1971 GMC has two relays (tcs and emission) on the engine side of firewall just above and to the right of the fuse panel. The Blazer doesn't have these relays. Does anyone know, is this a Blazer thing or a 1972 thing. I want to find a underhood harness but don't know if the harness would have to come out of a Blazer, or could it be out of a 1972 C or K truck also.

Re: 1972 Blazer Underhood Wiring
 

My TCS was on the cab side of the firewall.

Re: 1972 Blazer Underhood Wiring
 

Here is a picture of the TCS relays.
I think all 71 gmc and chevy vehicles with the 350 th had them even 6 cylinders. not certain however.

If you go to the search bar by your private messages and type in TCS then tick the 67-72 circle and click google you''ll get a lot of info in the tcs stuff.


Attachment 2216551

Re: 1972 Blazer Underhood Wiring
 

That set up is exactly what my 71 GMC has. I understand how it functions and it's purpose. What I was getting at is that the 72 Blazer that I'm rebuilding does not have these relays. My blazers transmission has no provision for an electrical plug, nor does the carburetor have the idle stop solenoid that accepts electrical connection from relay. This surprised me to see an emission component go away.

The question in my post was regarding how to obtain an engine harness for the Blazer. Engine harnesses with the relays won't help me unless I take them apart and change them, which I am trying to avoid.

Re: 1972 Blazer Underhood Wiring
 

I assume your talking about your 1972 Blazer? What transmission does it have?

Re: 1972 Blazer Underhood Wiring
 

One option might be to use an engine harness from an earlier year that didn't have the relays. The 68-69 version might suit your needs. If you have an HEI distributor, you can get a harness that is already modified to work with it. https://gmcpauls.com/wireharness_2.htm