TR2/3/3A wiper motor DR2 wiring - TR3A

[NutmegCT]

When I got my TR, the wipers worked fine, but didn't "auto park" when powered off. Just stopped dead when you cut the power at the dash switch.

I cleaned all exterior motor wiring connections, no change.

I removed the motor assembly, cleaned inside and out (found the copper "commutator" for the auto off was coated with thick hard grease).

Reinstalled the whole assembly, re-connected wiring, and still no change.

I also notice the wiring diagram (Advance) for the TR3A shows only two wires plus ground: a solid Black to terminal 1, a solid Green to terminal 2, and a Black to ground.

Mine has one Green with Black stripe wire on terminal 1, two Green wires (connected into one covered spade terminal) for terminal 2, and a smaller gauge Black to ground.

The panel switch has only On and Off. (single speed)

Could someone please check their TR3A DR2 motor wiring? I'm wondering if I just don't understand the Advance Wiring diagram, or perhaps my wiring is "creative". However, the wiring comes from the original fabric covering, and is quite old.

Any thoughts on why mine can't "auto park"?

Thanks.
Tom

 

[TR3driver]

I'm wondering if I just don't understand the Advance Wiring diagram, or perhaps my wiring is "creative".

No, Dan's schematic is "creative" in this area. What you have described is exactly correct for an earlier TR3A. Dan's diagram is missing a 'G' on the wire from the switch to the wiper motor (should be GB, not B), and shows the later configuration with the green wire from the brake light switch going to the fuse block directly instead of to the wiper motor.

Any thoughts on why mine can't "auto park"?

There is a wire that runs from the terminal on top of the wiper motor, through a hole in the housing, and connects to one of the brush holders inside the motor. I would guess that wire is broken or missing. You can test that theory by temporarily connecting a jumper from the terminal to ground, which should cause the motor to run all the time (when the key is on) even if the switch is off.

If that works, then either the motor itself is not grounded, or the brass finger isn't making contact with the commutator.

 

[NutmegCT]

Thanks Randall. I'll test that ground soon as I've repaired the hood hinge stud that just broke off (there was only one stud there - other hole was empty). Then I can safely open the hood again.

argh ......

Tom

 

[TR3driver]

soon as I've repaired the hood hinge stud that just broke off

Those things have GOT to be one of the weakest points on the car ! If everything isn't just exactly right, they break. And even if everything is just exactly right, they still break !

After breaking more than I care to count over the years, I now use a bottoming tap to carefully clean out the threads (to get maximum thread length), and Loctite to hold the (finger-tight) studs in place. That seems to help them last longer. Adding the (orignal) pads under the hinges seems to help too (although I cannot explain why).

Don't forget that there really are 4 different hinges, each hinge goes on a different corner.

 

[Don Elliott]

We just went through this yesterday (again) with the wiper motor on my early TR3A (TS 27489 LO). We fished around behind the central panel under the dash till we found a spot in the wiring where we got it to work. To stop it correctly, remove the wiper blades. Then loosen the 2 small hex head screws on the top of the wiper near the roung thingy. Rotate this thingy till you find the right spot where the blades will stop at the right place then put the blades back on.