Has anyone ever replaced thier wiring harness on a daily driver? My electrical system is totally on the fritz and I am thinking it might be better to just replace all that old copper...

How long or how much can I expect this to cost?

Doing it your self, unless you are an electricky guru, is a brave project even for the most seasoned home mechanics. About few hundred dollars and much much pain if doing it on your own.

A painless wiring system can lessen the mental anguish a little and can be found on the net eaisly with a simple search. They are about $700-800 Aus for a simple kit.

Or you can pay a sparky to do it. It then comes with a warrenty, no mental anguish, no hours lost in the shed, but at a significant cost. They cost heaps cause its a complicated process to get it right. From memory, my Dad had his old hilux quoted to be rewired for about $1500 - $2000 Aus, so its an expensive exercise. I am sure that one of the auto sparkies on this site should be able to give you a much better figure than I can.

Good luck.

i would think the hardest part would be using the correct size wires for each thing, but i guess if you go too nig it doesnt matter

i cant see why it would be all that difficult

i've considered doing it, but never really had the need

there isn't all that many things to wire up on a humble datsun and i think it wouldn't be hard to make it really neat too

i say try it and let me know how much of a pain it was

it would take ages, but if you make sure you have everything you need before you start it should be pretty straight forward

edit: at the end of the day the entire wiring diagram fits on half an A4 page in the car manual..... its really not that complex

its not the wire size you have to worry about its the quality of the wire and its sheilding, before becoming an avionics technition (sparky on helicopters) i didnt have much of a clue about wiring and i used the incorrect wire on my show qaulity xm falcon it seemed like the right wire because it was the same size but the sheilding and the resistance of the wire produced to much heat causing a massive melt down and lots of smoke scary in a car that youve just poured shiv tins of cash into.so when you choose wiring i now know that there are infact different qaulities of it, in aviation you use aviation standard wire which must pass a qaulity test, so in short get the right wiring the first time.

while I've never replaced a wiring loom becuase it's was an on it's way out - I am currently rebodying my March '77 120Y (B210) four door sedan into a spare July '74 120Y (B210)4 door shell

under the dashboard you will find 2 rectangular plugs - they hook up to the engine bay wiring undo these and the three bolts near the windscreen, the 2 that hold up the dashboard, and the 2 that hold the steering column up

and not to forget your speedo cable

and the whole dashboard is out

use a 1/4 drive set... otherwise you won't get anywhere...

apart from dashboard wiring and engine bay wiring loom I've switched over wiring looms...

those square plugs aren't easy though...

I may dremel the locking clips off if they don't unlock...

Yeah FTDTrainer

I think you hit the nail on the head. Getting good quality components are critical. You cant just buy the stuff from dodgy bros auto gear and expect a good result. I just bought a good soldering iron and that alone cost me $210. (Weller) If you are just going to get another existig harness and replace the old one, then yeah its easy. Just plug and play, but using an old harness defeats the purpose really.

The eaisest way to DIY is the Painless Wiring Systems. Still though, lots of hours in the shed, lots of fustrations, lots of burns, far too much anguish. If you are not in a hurry for the car, then yeah attempt it and learn heaps. Its something that I want to attempt one day. Just be prepeared for the elevated blood presure, the heart papatitions, nausea, and the pressure to get the car back on the road.

Are you getting the general idea that I dont reccommend it for anyone but experienced electricky gurus!!!
Painless wiring Catalogue

Let's put it this way: the 1200 harness *is* complicated. Newer cars are insanely complicated but the 1200's is sanely complicated - it has a lot of wires in it.

For flakiness, it is unlikely to be "old wires". Instead the connections get a bit corroded. Usually this clears it all up: disconnect each connector, clean them up, put a dab of electrical grease on them a push them firmly back together.

Detailed instructions, including photos, are in the wiki - Dashboard Removal and Wiring