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TR6 TR6 Wiring

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H

Herald63nut

Senior Member
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Gents,
I have a '72 TR6 that a previous owner took it upon himself to "fix" the wiring behind the dash. The result is a disabled light stalk, no hazard switch (light switch inserted where the hazard switch should be) and other assorted "work arounds". I am debating attempting to repair the harness or bit the bullet and install a new harness throughout the car. My questions are: how difficult is it to install a new harness and what tips/tricks do I need to be aware of in doing so? Thanks!
Bob
 
Hi Bob,
I'd recommend that you start by downloading the wire schematic from the AAW web site. This is the most accurate schematic available and it's free. There are some BCF members who helped Dan Masters in the development of the schematic. Then you might want to look at the wire harness and power block that AAW sells. This harness is considered by many to be the best available and at a very reasonable price. You can even download the instruction manual for your specific car. The one thing that is assumed with this harness is that you'll upgrade to a modern alternator, specifically a Delco. I guess the thought is that if you're upgrading all of your wires, relays and fuses why would you keep an "underpowered" alternator. I installed one of the first AAW TR6 harnesses 6 years ago and have never looked back. I can run everything electrical at the same time and the voltmeter hardly moves. The only blown fuses I've had were the times I stuck my hand up under the dash, knocked a hot connection that then found its way to ground.

It's a big job to do as just about every existing piece of wire will get removed. You need to locate a place for the power block and plan out how you want to run the wires. The directions are excellent as is the support should you need it. It doesn't require any special skills except soldering and the quality of the wire is such that you can use a mini butane torch in place of a soldering iron which makes it quite easy. All in all it's a great winter project.
 
I won't and can't argue with anything that Bob said. But I will suggest that there's nothing wrong with installing a new original-style harness, either! Whatever you decide to do, look at it as a tedious-yet-rewarding job that will take you a good, full weekend.

Over the years, I've encountered my fair share of cars like yours where some previous (or then-current) owner thought they were either "repairing" or "upgrading/improving" the wiring. 99% of the time, they had done neither and would've been far better off either leaving it alone completely or PROPERLY fixing what was "wrong"! The other 1% of the time was facing the daunting, nightmarish task of troubleshooting a "replacement" wire harness that had been built completely out of white zip cord or a similarly monochromatic scheme! :wall:
 
I have been installing a new harness in my car along with attending to a few other matters. Everything worked well on my car, so I was able to cut the wires short of each connection and simply unplug and plug matching colors. I ran into one wire that wasn't an identical match.

The harness came from TRF. The only differences are with the dashboard lamps being a modern pushin bulb similar to a #194 bulb. There are a lot of additional ground wires which can only be good.

I bought Dan Masters Electrical Maintenance Handbook which has been extremely helpful since it has a wiring diagram that is visible to the human eye.

Whichever route you decide to go, you should find it doable.

Good Luck!
 
Bob is right in what he suggest, but there are several other paths you can follow.

One, original harness and original weak alternator.

Two, original harness, upgrade to 95 amp alternator and change or add #4 gage wire from alternator to starter. My upgrade is a bolt on, plug and play. 95 Amp Alternator Swap

Three, Four & Five: any combination of these and Bob's above.
 
If you buy the BNR, 95amp alternator, be sure to ask them to "float" pack the unit. It took three tries to get one to me that wasn't damaged.
 
I've got the 75 amp alternator from BNR for my 76 TR6 and it was a perfect easy bolt on replacement (be sure if you have the later tr6 with the alternate mount to order the right one). I'm going to be going with the AAW harness when I put my TR6 back together, but that said, I'm also not going to be keeping my wiring 'stock' either. There are some circuits that I'll be taking out (the useless footwell courtesy lights, and the seatbelt buzzer), some that I'll be adding (seat heaters) and it looks like the AAW harness will do exactly what I want it to.
 
the rear harness is very easy, When I was painting last fall I found out that my rear harness was cut where it goes over the rear wheel arch and all wires were replaced with red ones, and I didnt have a tunnel light either, so I replace it and it was pretty easy to do, I also fixed the back up lights, the switch was bad, fixed it too and now I have a tunnel light and back up lights, Now if I get the courage I will replace the front harness, guess when I have the engine out for rebuild would be a good time to do it Yikes

Hondo
 
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