Tired of all the electrical problems so am going to replace all harnesses this winter. Any advice or recommendations? I've read all the posts I could find on this forum regarding the replacement and looks like most of it can be done pulling the dash, seats and console. Would be great to hear any hard learned experiences before I start.

 

I know your having trouble after reading your other thread, if the harness is in good shape I'd trouble shoot the issue at hand. The individual circuits are pretty simple and it's easier to replace 1 or 2 wires or a couple of terminals than replace the whole harness.

 

Replacing all the wiring harness as I did can be costly. When I restored my car I had all the harness off and saw how butchered they were. I just knew I did not want to put those harness's back on and then have to trouble shoot them. So I decided to replace them and I am glad I did. The decision to replace them is entirely up to you if you feel that its worth it or not to find the problems wrong with them.

I guess I could have done trouble shooting, but replacing them worked for me. I used M&H Electrical for all of my wiring. It was just plug and play.

 

Don't get me wrong, I can't go all the rest of the summer without driving it so I will fix the problem I have now. Many issues with wiring, desire to restore gauges and to do the interior floor correctly all play into this decision. I have the original color manual with the wiring schematics and have the combined knowledge of this forum. What can go wrong?

 

I shudder when I hear what can go wrong. My all time favorite is "Hold my beer and watch this".

 

If you:

take your time
can read a wiring diagram
know how to solder and use shrink wrap
know how to use a DVM or continuity tester

you should have no problem at all repairing your harnesses. You can test every circuit on the bench and know that they are all good before plugging them back in the car. I have completely gone thru and re-wrapped all the harnesses in my 66 and everything works perfectly and the harnesses look brand new.
I personally don't care for the aftermarket crimp butt-joint splices or terminals as they can work loose over time. I solder (and shrink wrap as appropriate) every connection I remake and will never have to worry about them working loose.
Good Luck!

 

That's what I did with my engine harness. Unplugged it, cut the wrap off, replaced a burnt alternator wire and a couple next to it. Then wrapped it back up and installed back on the car. There are not many wires.

 

I was going to replace mine when I had it out of the car but when I started looking at it closely it was just a coupe wires that were goofed up. Ended up replacing a couple and spent a lot of time with a Dremel tool with a little wire brush attachment cleaning terminals and rewraping. Most wiring problems in old cars come from bad grounds instead of bad wires. Good luck. Wiring can definitely be frustrating.

 

New dash harnesses are expensive but worth it IMO. I bought one from Lectric Limited for my 67, Just as M&H, their plug and play. They both make good harnesses. I have an M&H dash harness in my 65 Vette and finally that fixed my gas gauge and temp gauge problems. Im sorry but these harnesses are 40 to 50 years old and older I dont want to put in a dash harness only to find some new problem after installing it then having to start all over again. I changed to a Tic Toc Tac dash for my car and the harness that was with it just looked like trouble to me, so i have a nice shiney new one waiting to be plugged in.
There is also American Auto Wire who I think makes a good harness too.
Goodluck
Steve

 

Consider providing for HEI and internally regulated alt, if you're going that far. Also see clipsandfasteners.com for auveco wiring terminals and the plastic factory connectors. If you're going to put in a high amp alt, consider 10 or 8 gauge output wire.

 

Far as I know, American Autowire (AA) is making the harnesses and cables for almost everybody now including MH. Lectric Limited (LL) does make 'vette harnesses and modifies some others. If you buy a 442 harness from LL, it comes from American Autowire. TPP, Y1, etc. get them from AA.

 

Reproduction of factory harness as previously mentioned.
http://www.americanautowire.com/shop...F85&action=add

A easier schematic to read.
http://www.classiccarwiring.com/1969...iring-diagram/

Not hard to do just take your time, and take notes or photos of how each harness is routed.

 

I just replaced the dash harness and the engine harness in my '70 Cutlass. Actually, the insurance company did. I was able to get replacement harnesses from Restored Old Stock - ros6872.com for a terrific price.
The parts had been in secure storage for over 20 years and in excellent shape. Fuse block and headlight switch included. After market wiring kits are really expensive. Best of luck.