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Wiring Harness ID needed

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Tinkerman

Tinkerman

Darth Vader
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Morning all, was rummaging around in one of my parts boxes, electrical box in fact and found this harness. No tag of course. The overall length of the harness is about 60 inches. I bought a harness from British Wire for my 3A post 60000 car and he suspects that it might be an OD harness. It is wrapped in the same fashion as my new Harness.
Could it be an overdrive harness? If so would it be correct for three transmission isolator switches or would I need additional harness components?

Any and all thoughts appreciated.


Thanks, Tinkerman
 

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Yes, it's for an overdrive, and a relay will figure in the wiring as well. As for the isolator switches, I believe, most commonly, it's two.
 
You were probably thinking 3 because 3 gears have isolators. 3 & 4 use the same switch:

OD-Cover.JPG


For matching to your harness:

OD%20Wiring.JPG
 
At the very least, you'll need the 3-headed wire that connects to the isolator switches; plus the 3-headed black wire that grounds them.

I'm guessing it's also supposed to have another length of wire between that harness and the OD solenoid; but I could be mistaken on that point. But some solenoids have flat spade connects rather than bullets, so you may need a short adapter to deal with that at least.

PS, that looks nothing like the original harness from TS39781LO.
 
Morning All, I'm sorry to say that I was remiss in not mentioning that my tranny is a TR4 full syncro with 3 isolator switches.

Tinkerman
 
Tinkerman said:
Morning All, I'm sorry to say that I was remiss in not mentioning that my tranny is a TR4 full syncro with 3 isolator switches.
Click to expand...
The third switch is probably for reverse lights. Although I don't believe they became standard until later, some early cars were so equipped by the factory.

Another possibility is that someone swapped in the top cover from a later car, with seat belt interlocks.

In any case, only 2 of them are for the OD.
 
Thanks Randall, I seem to remember the third switch is for the reverse lights, Which, of course, I don't have.
I have since found out that what I have is the upper relay harness as built by British Wire and what I need is the wiring to the gearbox which they have.
Should I remove the third switch and plug the hole?

I thank all of you for your input.

Tinkerman
 
Or just leave the third switch in, connected to air. But be sure to choose the correct isolators for your OD, the two Geo Hahn has indicated in his photo.
 
If you don't opt for reverse lights (some license plate lights from later cars, mounted on the sides of the rear bumpers might look nice); I would suggest leaving the switch. The threads are an unusual size (M16x1 maybe) and so suitable plugs might be kind of scarce unless you've got an early non-OD gearbox handy to rob them from. And the old switch will make a fine plug.
 
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