I recently went back over my wiring harness assembly and found a discrepancy with the wiper motor and hooking up the heater. Because the car is a 1958, I was using wiring diagrams from both a tr3 and tr3a that I got on line sometime back. I googled some questions I had about the wiper switch and found an old post where Randall and Geo are helping a member with his wiring diagram.
Anyways, there was a second wire green coming of the fuel gauge wiring and “hermanmaire” (the member being help) struggled where to hook this wire. I have the same second green wire about 6 inches long with a bare end on my new harness. Then it hit me this second green wirer is for the heater motor and put on at the factory.
I figured the green wire was power for the wiper motor, and black and green was the other side, but when I looked into the old post deeper I saw how Geo talked about the ground wire is used for the switch on wiper motor with no power in play on the switch and Randall wrote about how only the very early tr2s used power on the wiper switch.
So I hooked the heater to the second green wire on the fuel gauge wiring and hooked the other side of the wiper switch to ground. This should work. The other way I had it would have let smoke out for sure.
So if you have a new wiring harness with 3 wires at the fuel gauge, the extra one if for the heater. The bummer was I had the oil gauge hooked up and center dash and the heater installed. I was able to rework the wires in place through the glove box hole, but challenging.
https://www.britishcarforum.com/bcf...R3-New-harness-install-wiring-questions/page2
thanks you guys--peace out!!!!