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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: Tduff01 on February 17, 2016, 09:18:01 pm

Title: under dash wiring harness compatibility.
Post by: Tduff01 on February 17, 2016, 09:18:01 pm

I have a 1978 K20 Scottsdale 350 4 speed. My under dash harness has unfortunately been hacked up from some previous owner. I have an under dash harness from a 1980 1-ton Chevy, I don't know anything else about the 1980 truck. My question is will these under dash harness just interchange and I can just plug n play with the 1980 harness in my 78? If not what issues will I most likely run into? Any help will be greatly appreciated. Will be working on the truck this weekend.
Thank you in advance for any help or information.

Title: Re: under dash wiring harness compatibility.
Post by: hatzie on February 18, 2016, 12:28:36 am

People change from the class cartridge fuse to ATC panels all the time. 

1978 & 1980 actually used the same three bulkhead plugs to mate the cab and engine compartment sides of the firewall.  Download the wiring manuals for 1978 & 1980 to compare the wiring pinouts.  You can re-pin the bulkhead plugs if you have to.

Title: Re: under dash wiring harness compatibility.
Post by: Tduff01 on February 18, 2016, 08:11:41 am

Thank you. I will be working on it this weekend. We will see how it goes.