ECM Harness Removal

[Kempster707]

Hello Everyone,

This is my first post on Squarebody. I will be replacing the cab on my '75 C10 with one that is rust free. So, I am currently removing all the electrical in the cab, and I am wondering how in the heck I am going to snake my LS motor wiring harness back out the hole in my firewall without 1) Possibly unplugging all the connectors from the ECU and try and get them back out through the hole, or 2) Disconnect ALL the wires of the harness from the engine ? Way out of my wheelhouse.

 

[YakkoWarner]

I'd probably unplug at the ECU end (although in the interest of full disclosure I am not familiar with the LS motor wiring). At least on that end you know exactly where they go - its easy to label each one as they unplug (and I'd like to hope they are designed to only fit one way anyway). Will they fit thru the firewall once unplugged though? If not you may have to go the harder way and disconnect each one at the engine. On the old cab making a bigger hole is an option (just don't damage the wires in the process), but I assume you don't want to hack up your rust free replacement cab to get it back in.

 

[Kempster707]

Thank you! Yeah, with someone who knows how to wire these engines it might not be a big deal, I need to find that person, so I don't screw it up!

 

[Ricko1966]

If the plugs on the ECM won't fit through the hole nbd. There's not that much attached to the engine,most of the plugs are specific meaning,you can't plug them in to the wrong socket. And here's the big tip. Put a stripe of regular old white out or white brush touch touch up paint out on every connector you need to remove and the component where it attaches,let the stripes dry. Now grab a 15 pack of sharpies,put 1 red stripe across the white out stripe at one connection and it's component. Then a blue stripe on the next etc,etc. If you run out of colors double up white red blue,white red green,etc etc.now stand back and take a picture. Going back is fast an easy you have while yellow blue in your hand look for white yellow blue on the engine, plug in continue. Faster than numbers or labels and the pic you can look at to verify how things were.

 

[Kempster707]

Rick, I totally agree with you, color labeling is the only way to go, plus you will feel like an artist once you're done . Thank you!