The Stovebolt Site Forums The Shop Area The Electrical Bay Installing a new wiring Harness.... where to start?

I have gotten to the point of installing the new wiring harness in my 53/54. How have you guys tackled this before? do you just remove the old harness complete and start with no wiring in place or do you go component by component? I don't see the room for a component by component swap, but that makes the most sense to me.
The old harness has been significantly hacked over the years and I have alot of stray wires and added wires for who know what was added and removed over the years. I was thinking of just removing everything and starting fresh but a little intimidated for fear that I might foul something up.

At this point I want to be able to get the truck on the road this year. I will not be doing any major cab metalwork or paint- so the new harness will need to come out next year (or when I get to the body and paint work) Mechanically I think I am set (brake system 100% new, rebuilt head and engine running well now) last step is getting the electrical system in order.

Any advice would be very much appreciated

Depending on the instructions that came with your harness, its surprisingly easy.

I removed all the wires

Laid out the harness in the garage

On paper I drew out each circuit, using the wiring diagram

The most difficult part is the under dash work

I started by laying the two gauge clusters and light switch out on a table and orienting everything like it would be once installed... then following the wiring diagram I wired the back of both gauges and light switch while I had easy access. Once they were wired I slid everything up into the dash and attached them... seemed easier than trying to make sure everything was correct while working under the dash...

Once the gauges and light switch were in I fed the remainder of the harness through the firewall and completed the rest of the terminations. I took my time and didn't rush and still was an easy job to finish in a weekend.

ok that's very helpful- I have the harness laid out in the bed now- the instructions that came with the harness show the main connections as they relate to main components (starter, headlight switch, ect) and everything is labeled- so I am guessing it should go smoothly. I plan on doing the swap this weekend so I'll post on the progress after the weekend. Realistically the wiring should be simple it just looks intimidating because there were so many modification and splices in the harness, added switches and lights, and levers all over the place from when it was used as a wrecker. all of the added items will go away with the exception of a lighted switch that I'll use to turn on the fog lights...
I'm looking forward to going back to a stock wiring setup that I can make additions too as I go along if need be.

Mostly looking forward to being able to take the truck out of the garage for some windshield time- on the road. With any luck it should be wrapped up after the weekend.

I rewired my '55 1st series in 2001. I'm not good at 'tricity and everytime I learn something about it, it rolls off my mind like teflon in a day or two.

I didn't like or understand the single page of instructions that came with my harness so I set about with a volt meter to find out where each wire in my harness went and to draw up my own wiring diagram.

When it came time to do the deed, it took two days of the four allotted and no fire extinguishers were harmed during the startup process.

My Shop log entry on the rewiring is here and along the left side of the webpage are links to my wiring diagram and individual circuit diagrams in pdf file format.

http://www.laroke.com/larryk4674/2001/wip13a.htm

Great decision to re-wire. Which wire harness have you decided on and is it vinyl or fabric coated?
Are you replacing the light switch and putting in a fuse panel?

There really isnt much wiring in these trucks compared to nowa days!

LAROKE- Thanks for the link! yeowsers on the "diagram" they gave you!

I believe I have the Classic Chevy Harness- plastic coated wires. No fuse panel and I am running my generator (12 volts) I'll have to grab the receipt/ instructions tonight to be sure of who produces the harness. I'll follow up with that info.

http://www.classicparts.com/1953-54-Wiring-Harness-Generator/productinfo/52-025/#

Here is the harness I have-

ah yes the wire harness days....

about 2 years ago before my truck was on the road i installed a new harness and had everything all trucked away nicely and neat. I stored my truck that winter under a huge tarp to keep the blowing snow away from it. Well the tarp never kept out nature and a cat made a home in it. It decided to mark my truck as its own and actually spray a few times in the exact spot. that spot was actually up in arc to the underside of my dash on the drivers side right where my nice main harness and fuse block was.

That spring it required a complete tear down and interior sand blasting and new primer. The full wire harness from bumper to bumper had to come out and be hand washed a few times using different chemical to remove the ammonia crystals from the fuse box. Now im a master at removing and installing harnesses.

Just thought i would share that story.

I'm about to tackle the same project myself. Good luck!

ok! wire harness weekend was less than thrilling but I have the main harness installed- it went surprisingly easy. I had ALOT of added switched/extra wires everywhere the harness is so much simpler than the wiring that was in the truck- I'm not running all the extra lights this rig did at one time ( it was converted to a wrecker at some point in it's life)the harness simplifies everything back to original. in two days over maybe 8-9 hours total I have the harness in ( gauges not mounted yet) a couple points on my installation:

- The harness I bough has a few extra wires that were marked but not called out on the instructions. Maybe I'm missing a sheet- I bough the harness awhile ago and it's possible that a sheet was misplaced but a phone call should clear it up

- I started backwards and installed the engine compartment section of the harness first- that seemed the easiest for me at the time- but I can see an advantage of installing the switch and gauge wiring out of the truck and will probably do that next time. it was a bit of a fight with the gauges behind the dash.

- I am nowhere near as skinny as I once was- nor as limber! working through the dash holes - gauges removed- made things easier but there was significant laying and bending and craning of the ol' neck that I paid a price for that night

- I should have had a factory wiring diagram with me as I did the swap- would have made things a bit easier to correlate- for example The generator leads I am unsure of which was which and I might possibly have them reversed-

- Dome light wiring connector was very brittle and I broke the connector on the back side as I tried to install the light - ugh.... need a dome light assembly now

- My headlight switch is not as reliable as I thought it might have been it's a bit sloppy- so I'll be in the market for a new switch- should have just had a new one to begin with.

- Tail lights. the kit gets the harness to under the bed and they provide/have bullet connectors on the wiring-along with extra correlating wires to get me to the tail lights- those are next.

- I have a third brake light/ plate light that I mounted to the head of the bed, so dropping the wiring down and connecting to the tail light section of the harness should be simple enough.

- Routing for the passenger side headlight is a bit unclear as there was no wiring there when I received the truck- so the harness runs in front of the radiator. that's the shortest route and I think that is correct as the harness (due to length) could be routed underneath.

- The plan here was to get Mo on the road as-is and concentrate my efforts with getting the wife's truck built this year (basket case but complete - I think), so I'm putting a new harness into a grungy cab and there is plenty of dirt and rust. I don't think I would do that again- it's almost counter-productive knowing all this will need to come out again when the cab is restored - I could have possible patched the old harness enough to get gauges and lights working.

So I still need to get things tidied up and the gauges back in- the generator leads need to be addressed (which post is which?), as well as tail lights squared away. I also need new bulb holder assemblies for the front indicators- mine were rusted beyond recovery.

I did get to see the headlights light for the first time since owning the truck! so I go that going for me

F post on my 12 volt generator is the post farthest away from the motor. The stamp is very faint and I can't believe I didn't notice it before. What happens if the A and F post wiring is reversed when the engine is running?