Wiring Harness - Fire & Smoke

[saborstyle]

Hello, first post here. I picked up a 72 C20 this summer to help move some stuff back and forth from my business. I wanted to get a truck and always wanted an older one so I made it happen. It has been pretty good, sans some brake line issues and what not. I have some goals to remove the rust and body work etc, but that all takes time.

Anyway, my urgency for the post is I started up the truck this weekend and started getting some smoke under the dash. I frantically started looking, opened the hood and found saw more smoke. I went back under the dash and saw 2 red hot wires so I kind of kicked at them to get them to quit touching and they cooled off and the smoke stopped. I disconnected the battery and started to troubleshoot.

I have some pictures. It looks like some wires for perhaps the rear tail lights crossed, melted and caused other wires to melt. I am attaching pictures. My question is how major of a repair is this? I cut the wire to the brake lights, tried to make the wires not touch and separated them. However, now my turn signal clicks, tail lights don't work. Also, last night I was driving and head lights went out. So, needless to say something is pretty screwed. Any input would be great. I have an LMC and brothers catalog but have never ordered anything.

72 C20
V8 350?

Thanks!

http://www.flickr.com/photos/1180146...7641174222834/

This is a flickr link. I think it will work fine.

[sstaten69]

Wow know that's scary. Looks like someone put in a piece of tubing for a fuse. I don't know if that caused it but don't think its a good idea to have it in there. good luck.

[engineer_gregh]

The orange and white wires are for your interior light, I believe. They can sometimes short under the sill plate.

[saborstyle]

So I guess i can replace that entire fuse box but I don't need to rewire the entire truck do i? I mean there is a big bundle of wires coming out of the fuse box that needs to be replaced but I hope that is not everything. Any ideas?

Thanks

[engineer_gregh]

Kind of hard to tell from the pictures. If you are comfortable with rewiring on your own I would give it a shot. If not I would find a shop and get some expert advice.

[saborstyle]

I have never done a rewire. The truck its self does not need to be used too often so i could attempt it. I am all for learning as long as it is not overwhelming. It also depends on the cost. I mean if its $1500+ to get it rewired I may try to attempt it myself. I may have to try to get a quote. Be nice if I knew somewhere decent in West Houston/Katy.

[engineer_gregh]

I'm sure that someone on this board is close by and could give some advice on nearby shops or even stop by and give some in person advice. This is a great board.

[engineer_gregh]

Might not be a bad idea to start a new thread asking for help listing your physical location and problem. If I was closer I would lend a hand:-)

[Bears63]

With all that melting I would most definitely replace the main underdash harness. I faced the same situation with my '71 a few years back and I didn't chance it, I replaced the whole harness. If you don't you may chase electrical gremlins until kingdom comes.

That harness pretty much drives everything. If you replace the harness with a stock replacement it isn't a bad job, just time consuming as you have to tear most everything off/out of the dash. It's pretty doable yourself, just take lots of pictures of how the harness is routed before you yank it out.

[70STOVEBOLT]

I agree with Bears63. Most of the wiring connections are plug and play on the underdash harness. Check the parts board for trucks being parted. Any harness/fuse block from 67-72 should work. If you have a/c, it works, and you want to keep it working, you will need to find one from an a/c truck. If you are going to repair your harness, there is a color wiring diagram in the Electrical FAQ section that will be helpful. Good luck and welcome to the site!

[mrolds88]

Another harness would do you good. One thing I would do would to find a donor truck locally. Take it apart yourself. Taking pictures and label the plugs. If you take your time, I think you will do alright. I'm glad you got everything under control before it got worse!!!

[BB72CHEVKT]

I spent about $1300 with parts to have a painless harness installed.

[magwakeenercew2jh]

http://www.wiringharness.com/PDFS/TR...hevy_Truck.pdf

This is the page for the M & H harness I always crow about.

I think it's $409. I'm a moron and I wired both of my trucks from front to back with M & H harnesses.

In the case, as much as can be understood from those pictures, anyway, you'll need to change out the fuse block and under dash harness
(it's all inclusive in the $409) if you want to get any "sleep" while you are driving your truck.

Remember, something shorted out. No sense buying and installing the new harness unless you know what fu'd on you. Like engineer_g,
I think it was the wiring in the area of the rear interior light and the dimmer switch that go down by your left leg and under the door sill.
Someone hooked something there that bypassed a proper fusing....Happens. And melted hots don't go well with melted grounds.

It's really easy...Get the harness. Pull out the old crap. I'd buy a new dimmer switch. Look at the wiring diagram that Forum members
have made available....Then plug and play with the new harness.

[Tom Vogel]

^^^^^ Truer words were never spoken. M&H or AAW... and do it yourself. Call Wes at Classic Heartbeat.
Re: Painless... No, No... no.