The Stovebolt Site Forums The Shop Area The Electrical Bay New wiring loom installation advice

I’m about to tackle the job of fitting a compete new Jim Carter loom into my 49 Suburban which currently has no wiring at all

I’ve not done this on a Chevy before so I’m looking for any advise or links to good guides or videos before I make a start as I’m not totally sure on the routing

Thanks
Mike

I will be doing one on a '53 3100 soon, and I plan on wiring the harness to the gauge cluster and ignition switch on the bench, then install the pre-assembled works into the truck.
I am pretty sure that was how it was done on the assembly line. If you ever looked at the back of an original gauge cluster with original cloth wires on it, you will see how impossible it would be to make it look like that while on your back, bent like a pretzel.
Carl

When I did my '48 1.5ton with a JIm Carter cloth harness I removed the headlight switch and connected to it first, then I connected to each gauge and installed them one by one. Then I passed the harness thru the firewall and connected to the fuse box, headlight connectors, and engine bay. I laid the new harness out beside the truck and studied it for a while before installing it. I printed a colored wiring diagram to refer to, instead of dragging the manual around with me.
Good luck, Curt

Thanks Curt! I forgot about the headlight switch! My neck and back hurts right now just thinking about hooking up all of those wires all twisted up like a pretzel.
Carl

Working under the dash is painful in a variety of ways. To make the physical part of it somewhat easier a buddy suggested I make a “bed”. It’s fairly simple. A plywood plank wide enough to fit between the seat bottom and toe board. And long enough to rest securely inside the cab, about 1/3 to 1/2 way and protruding outside the cab about 18” or so. The outside end of the plank has legs, somewhat similar to a long folding table, fastened to it. Then add a foam rubber or similar mattress. Worked like a charm for me. I think I even took a couple short naps along the way.🤫

My main concern is the routing such as coming through the right holes in the firewall and the routing to the back of the car as I have no point of reference

Many of these routings are detailed in the 47-54 FAM (Factory Assembly Manual).

I'm going to try this out - as well as pushing the clutch pedal in and dis-connecting the brake pedal from the master brake cylinder, then pushing it down for more head room.

801curt has the best advice as I see it. The harness is sort of self supporting (I know there are some clips) so there is very little slack in the wires. When I have to work on mine now, I remove the radio grill and the speedometer first. I don't attempt to get my head under there because for me, that is too hard on the neck. Leaving the headlight switch dangling until the instruments are done will make life a lot easier.

You are on the right track to think ahead about how to best complete this work. It is not technically challenging but needs to be well planned. My experience is that routing is the key.

Anyone with basic skills can connect wire A to terminal 1 etc. That is not the measure of success for this work.

I agree that the AD assembly manual is a tremendous help. The fact that you are working on a '53 means it will be much more relevant than it was for the '49 we just completed.

We were in the same situation that you are. The truck had no wiring. Over the 6 months prior to installing the harness we looked at many different AD trucks and took lots of pictures. That really helped but it also has some limitations. If the person who did that installation did it wrong, then we might end up doing it wrong. After looking at about a half dozen trucks we quickly learned what was probably more appropriate.