The Stovebolt Site Forums The Shop Area The Electrical Bay Wiring Harness Question

I have come to the realization that the wiring in my '37 is so poor that I have to take the plunge and install the new wiring harness that came with it when I bought it before I'll be able to get everything hooked up...

My question is, what is the best way of going about replacing really messed up wiring in my truck? There seems little point in following what is already there as it is half disconnected and the other half completely "Mickey Moused" together with multiple splices and wire colors all in the course of just about any given wire...

Is my best plan of action to just tear out ALL the wiring and start right from scratch with nothing in the way? Not sure of the brand of the wiring harness but it says it was made in Brazil and seems to be pretty good quality...

Today we laid it out and labelled the ends of every wire using the schematic so I'm pretty much ready to go for it... I just wanted the opinions of those who have taken on a job like this before to see what works best...

Oh one last thing... I also just purchased a new Ididit steering column because the wiring on the old column was really mangled too...

Would it be in my best interest to install the new steering column first so I have GOOD wiring to connect to or should I rewire everything else I can and THEN install the new steering column?

Your thoughts? Thanks in advance...

~Trev

I vote to remove the old junk and start with a clean slate. That is the way I did mine. It also might be easier with the column out of the way when under the dash. just my 2c.

37, I have to agree with 235 on this. Remove all the old wiring first, then start fresh. This is what I did with Dusty, and it made the job a LOT easier! Installing the new steering column also sounds like a good choice. Out with the old, and in with the new. Let us know how it goes along.

I am agreeing but disagreeing with 235 Fat Fender and Brian56. Yes, DO put in all new wiring as they recommend but I don't just tear the old stuff out by the roots. I used the old wiring 'paths' as a guild. Either make very good notes or take a ton of pictures, you can't take too many, of the wiring if you are going to start with a 'clean slate'. You may also need to renew the gromments and sleeves at pinch or rub points. If you just pull it all out at once you may not remember where these need to be.

Good Tip Beltfed ..I just ripped everything out an started NEW...it all worked out but i RE-Did allot because of puttin it HIGH when it shoulda been LOW ..an vise-versa ..the original flow of wires should be kept as close as possible ..they ran em that way for a reason ..AN THEY DIDNT HAVE A COMPUTER THEN !...hmmmm makes ya think !

I just ripped out the old before putting in the new. If your present wiring is such a conglomeration it may only serve to confuse you. However, it never hurts to make note of the present configuration. I think the process is easy enough that you won't get lost.

If you have a wiring schematic in a truck manual for that year it would also help. I rewired my stock 49 one wire at a time replacing as I went. I used the schematic in the book to confirm wire gauge.
As far as color goes I went against conventional wisdom by making mine all black in the engine compartment because there are only a few wires, headlights, generator, parking lights, horn and the longest run from the fuse box to the terminals is only a few feet. Easily traced if need be.
However wires under the dash and going back to the tail lights and gas tank sender I did use color. On the 49 the wiring is pretty simple.

I especially agree with taking the steering column out. It makes working in an already confined space a lot easier.

Thanks for the comments guys...

My vote has been to pull it all out too... as my buddy said when he saw the wiring under the dash, he didn't know if he should work on it or go look for some spaghetti sauce to put on it... It is a tangled mess and there's not too much hooked up there to start with!

I think taking note of the flow of the wires would be great but there really is no method to the madness anyway... I'll make note of which wires exit the cab where and try to go with that I think!...

One other thing I was considering doing since almost everything under the dash has inline fuses built into the wires... For the sake of cleaning THAT up I was going to visit an auto wrecker and pick up a nice fuse box, preferably one with the turn relay built right in... that way I can run ALL wiring to just one area in the cab, get rid of all the inline fuses and just run wires to what I need from there...

In my humble opinion it should make things cleaner and simpler for me than the way it is now...

Can't wait to install the Ididit steering column and get rid of the old crappy GM one either... brushed aluminum is going to look nice in there and brand new wiring to attach to is going to be a treat!

~Trev

oldblu...
The wiring harness I have has multiple color wires, but they are either wrapped or shrink wrapped so they have a neat, clean appearance...

Now that they are all labelled as to their locations it should be a lot easier install and if I get lost I can always peek inside the shrink wrap for a green or red or blue wire and figure out what I'm doing again...

~Trev

I agree and really can't wait to get that messed up old GM Column out of there... it would be nice not to be looking at the melted wires that are on it and have the extra space to work...

I also think I'm going to try to pull my guages out of the dash as well since the previous owners did a really cheesy installation of those as well...

Being able to work through the dash rather than under it with the guages, glove box and steering wheel removed it should be a much easier process... In these old '37's you don't have enough room to swing a cat so I'm going to need all the room I've got

~Trev

You mentioned you may get a later style fuse panel with the flasher installed, If you do that and have enough wire in your harness, mount that somewhere that is visible in dim light and you don't have to stand on your head, or kneel in the mud on a rainy night to check a fuse

Slomotion...

You read my mind! lol

Luckily 37's being the height they are and having running boards to kneel on while looking under the dash, there's not much danger of having to get down in the mud!

However for the purposes of it being easily accessible to wire the truck and get to later if I want to add anything or need to replace a fuse, I plan on putting it where I find them in most of the cars I have driven... on the drivers side wall in front of the door, under the dash...

It should work great there and be really easy to run all the wires to that area to attach to the fuse box too...

~Trev

One suggestion, lay the wiring harness out on the floor outside out of the truck first. Put all the wires together that are headed for the same place (e.g. underhood, rear, dash). Makes it much easier than trying to read the tiny lettering on the wire while laying upside down under the dash.

absolutely do this.
also think about what you ''may do'' in the future and add it now. ie back up lights, fog lights, any switches you think of, speakers and/or modern radio, modern cig lighter w/ light, hidden 'kill' button, add more ((grounds- cab to frame to bed to radiator frame to tail end,tail lights)), relays (for at least the headlights & horn). LED dash lights for bilnkers (green), alt (amber), low oil pressure(red) and highbeams (blue). LED taillights.
http://s67.photobucket.com/albums/h298/1951otter/?action=view&current=10A.jpg
and a three wire alternator >>>> LED dash light for alt idiot lamp (amber).

i made my own wiring harness (cause the PO started but used ALL red wires.
his whole complete diagram fit on one page of binder paper.
i added 6 relays for the higher wattage uses. a new (10 position) haywire fuse block.
terminal distribution blocks
http://www.madelectrical.com/catalog/cn-1.shtml
http://www.madelectrical.com/catalog.shtml
3 or 4 fuse links (homemade) but are avail @ napa or
http://www.madelectrical.com/catalog/fusible-link.shtml
water proof connect plugs,
molex connectors ... http://www.action-electronics.com/molex.htm#Standard
heat shrink tubing, soldered.
split wire tubing like this ... http://cableorganizer.com/wire-loom/
COMPLETE accurate wiring diagram
just great fun doing this project.
WHAT an education this has been.

Caroline and Jim...

The only thing I was thinking of adding later was a good stereo or radio hidden away out of sight in the truck somewhere but I was seriously considering just running the wires I would need for it to the location I would probably have it in now, then labelling them and taping them off so it would be an easy install on that later as well...

Thanks for the rest of your suggestion though... nice to see so many who have done this wiring offer their advice... thanks everyone!

~Trev

I also am reaching this rewiring point and don't have any clue but my game plan is to buy a 8 circuit or better harness and mount in glove box with radio. Rebel wire has the harness relatively reasonable. I have no interior in place, only insulation, and plan to run wires for a dome light and possibly for electric wipers. Agree with others above on wheel, guages, and glove box removal for access. Pics below

Dan
http://rides.webshots.com/photo/2036333900071274430HANLJn

I wish I knew what make my harness was so I could give you a heads up, Chev... It seems to be very well made (according to my buddy who is an electrical technician) but since I am not the one who bought it all I can go on is the paperwork that is with it... It only says "Made in Brazil" so I have no idea...

I've heard there are some good harnesses out there, many favored by hot rodders so I'm sure you'll find something good that will do the job... good luck to both of us... we're gonna need it

~Trev

I ran all my wires under the seat since I moved the fuel tank. Theres lots of room under there and it was pretty easy to get to. I ran all the outside wires out under the cab and the inside wires up under the dash by the left kick panel and under the carpet. I had a lot of wires from the dash area because I ran everything to and from the dash back to the same point under the seat. Nothing thru the firewall. I used a lot of relays to keep the heavy current out of the dash. Joe