TR3A Wiper motor wiring

> We've got the reprint of the TR2 Shop manual with the TR3 supplement and our TR3A wiper motor does not operate wired according to the manual

The only accurate wiring diagram for the TR3A is in the owner's handbook. The earlier electrical systems are subtly different, including how the wiper motor is wired.

> Would a positive ground to negative ground be significant?

No. I converted my car years ago and made no change to the wiper wiring.

> a red wire going from the motor to the top of the gear box (which is hot when number 1 is hot - 12 volts) and appears to be insulated from the gearbox cover.

This wire is going to the park switch; power goes through this circuit after you turn off the panel switch and until the wipers return to 'home' position and then open this park switch, stopping the motor. You adjust the stop position by loosening and slightly rotating the cover.

> On my car We have a post numbered 1 and a post number 2 along with one labeled 'E' on the motor.

The three wires connected to the motor from top to bottom are:

(Top) black - Ground, also known as 'E'arth connected to the motor case

(Middle) green - 12V from fuse block

(Bottom) green / black tracer - to wiper switch on dash

(the wiper switch completes the circuit to ground to operate the motor.)

There is also another black ground wire in the harness that is fastened with a ring connector to the wiper motor mount using one of the body bolts.

Brent Smith

Return to the page top