Basic wiring loom resto

Anonymous · Post by **Anonymous** » Wed Aug 10, 05 7:09 pm

The wiring on these thirty plus year old cars can be a bit of a nightmare. People add and delete electrical parts, the wiring goes hard and brittle and the engine harness gets repeatedly heated up. The upshot of this is frayed cables touching each other or earthing against the body. It looks bad and at worst can cause a fire.

There were alsorts of odd bits of wiring under the dash of my T/A and I removed seven cables that werent doing anything anymore. Im sure most of this applies to any old Mopar (or any car really) and hope it comes in handy

When I took a closer look at the engine wiring loom, it looked awful, the wrong coloured bits of wire were connected to the wrong items, this makes fault diagnosis a bit of a laugh.
So I decided to remove the loom complete from the engine bay, and restore it. There are three options here, buy a complete new loom from a dealer (like Year One), best for reliability and NOS appearence - but very pricey, buy a loom kit which will include all new wiring and some connectors - cheaper, or restore what you have with some new wiring and connectors.
I went for the latter.

Before you commence the job, start the car and check all electrical items that are connected to the loom involved. Nothing worse than completing the job, finding something dosent work and not knowing for sure whether it worked before the job or not.

First job is to label (and take digi pics) and remove all the plugs and connectors from the terminals of the various componants. Labeling is absolutely vital here, I started at the front with the washer pump, horns, three alternator wires, electronic ignition control box plug, water temp sender, coil, dizzy alternator regulator plug, ballast resistor, and finally the eight pin bulkhead plug. I found a couple of cables that didnt do anything, including one that ran from the ACC live on the fuse box, through the bulkhead, under the floor pans and terminated in a bare end a few mils from the fuel tank - hmm fun!

Then remove what is ineffect two looms from the engine bay very carefully, and retain the shape of them, then lay them on the a nice clean flat surface.
I frst removed the black wrap tape from the terminals to the main loom, and this is where most of the damage was. One six inch length of the alternator wiring was comprised of four bits of different colour wire all twiddled together, not even soldered. Many other terminal plugs where held to the cable by a couple of strands of bare wire. I was amazed how well it had all worked!

I then removed the black wrap from the rest of the loom, taking great care to retain the original shape of the loom (ie the bends). Where various cables exit the main loom, I marked by wrapping a ring of electrical tape around that point. All cables where cleaned with a light amount of white spirit on a rag, this removes oil and brings up the cable colours nicely, dont over do it though.

All I needed for this job was a pair of combination wire strippers, crimpers and cutters, a decent roll of black electrical tape, quality assorted connectors, and lengths of variously coloured wiring.
All damaged wiring was cut back until a decent length was found, and using correct colour wiring and propper wire connectors, was made good. New terminals of the correct types were crimped on, I borrowed a mates set of ratchet crimpers, and these work fantasticly.

After all the wiring and connectors were made good, I started the task of rewrapping the loom. This was the longest part of the job and is definatly worth taking time over, as it is very visual when you refit the loom. Its worth buying a very high quality electrical tape for this and you will need quite a bit, mine had a satin finish which looks better than gloss.
Leaving three or so inches of cable bare, I started by wrapping the wiring that goes from the various connectors and plugs to the loom first, and then the main loom after. This traps the branch off wrap quite nicely and gives a better finished look. Gently pulling on the tape as you spiral bind the wiring makes a nice tidy fuel and oil proof finish.

After the job is complete you are left with no odd wires, frayed terminal ends and you will have a beautiful wiring loom before you!
I refitted the loom in the exact order that I removed it from the engine bay, it just seemed easier.

latil · Post by **latil** » Wed Aug 10, 05 10:52 pm

And to think you could have just bought a fire extinguisher

A tidy job and well worth doing, have fun under the dash

MrNorm · Post by **MrNorm** » Thu Aug 11, 05 11:58 am

Good job, I agree on the good quality tape. Scotch Super 33+ has come highly recommended for this purpose, it doesn't ooze at high temperatures like cheap tapes, and is a good match for the original tape (which was actually non-sticky, but that stuff is expensive, plus why would you??). So that's what I've used you might have to hunt around a bit.

For the interior looms where they are covered with a rubberised cloth tape, this is called friction tape and I've not been able to find it in this country (doesn't mean to say you can't get it mind) so I got some from the US, 3M again as you don't want to do it twice. I assume they used the cloth tape to stop rattles or something.

Anyway, once cleaned inspected and repaired or rewrapped they look as good as new. Mopar Muscle once gave a tech tip about soaking the old wiring in Armour All to help revitalise the insulation, but when I posted about that in the US some time back it got a distinctly lukewarm reception, so don't know if that has any merit. Obviously it won't help if the insulation is cracked or missing!

Dave-R · Post by **Dave-R** » Thu Aug 11, 05 1:06 pm

I have given up on the Chrysler wiring now that the bulkhead connecter has burnt out yet again.

I am going to fit a complete new system using the "painless" Universal muscle car wiring kit.
http://store.summitracing.com/default.a ... 03&FROM=MG

I will just blank over where the bulkhead connector is now and put the grommet that comes with the kit in there instead.

Anonymous · Post by **Anonymous** » Thu Aug 11, 05 4:20 pm

You can get a Painless 'Muscle car' kit which features a bulkhead disconnect and it fits and replaces the standard mopar one.
Gavin the tape is very important, I got mine from airfield leccys, meant to have thermal as well as electrical insulation properties.

Dave-R · Post by **Dave-R** » Thu Aug 11, 05 4:50 pm

I will look into that James thanks. But if anyone knows the part number that would be great.

Anonymous · Post by **Anonymous** » Thu Aug 11, 05 5:22 pm

#20103

Dave-R · Post by **Dave-R** » Thu Aug 11, 05 6:29 pm

That's the one I had in mind and linked to!

Are you sure that is a bulkhead connector? Everyone I have heard of using these kits has used a grommet in the bulkhead.

Anonymous · Post by **Anonymous** » Thu Aug 11, 05 6:48 pm

I cant remember who put me on to this, but they said that the fuse box/connector fits and works exactly like the mopar original, and Painless' description of the item seems to back that up. Probably best to give em a ring or email to find out for sure.

Anonymous · Post by **Anonymous** » Thu Aug 11, 05 6:50 pm

Just seen read your link, I would be tempted to get it direct from Painless.

Dave-R · Post by **Dave-R** » Thu Aug 11, 05 6:52 pm

Still it has to be better than the Chrysler original eh?

Anonymous · Post by **Anonymous** » Thu Aug 11, 05 7:16 pm

I always prefer original, where possible. My loom was well within repair limits and now I have full faith in it both for safety and performance. It can get to a stage where it is useless and dangerous though, my Rovers' is like that!

MrNorm · Post by **MrNorm** » Thu Aug 11, 05 10:09 pm

If cleaned and packed with dielectric grease the Chrysler bulkhead connectors should be OK. Their main weak point is where the full alternator current goes through the connector to get to the ammeter. If you bypass the ammeter or fit a shunt then the rest of the connector should be OK really.

But as always YMMV!! My original, non-cleaned, non-greased, non-shunted connector never missed a beat in the 17 years I drove it! No doubt when it's back on the road with the improvements it will probably go wrong

Dave-R · Post by **Dave-R** » Fri Aug 12, 05 9:03 am

I have cleaned mine up twice, replaced the engine harness. By-passed the alt wire to the amp gauge. But still if you go around the circuits with a volt meter there are losses all over the place.

Also as there is only one terminal for accessories on the fusebox all the accessory current is on one fuse/spade and I don't like that.