gerlando

Both! Here's a recap...I've only had the car since the spring and the rear wiper has never worked for me.

The front ones worked just fine, then the wiper stalk controls suddendly stopped working, but intermittent was fine. A couple weeks later the intermittent stopped as well.

I've checked all fuses and swapped them out even though they looked fine.

Last weekend I took the rear wiper motor apart, inspected, reoiled it, bench tested it and it would run. It didn't appear to be very strong and it would get stuck. I've taken the whole rear wiper assembly out at this point. I'd like a working rear wiper but don't think it's important enough to warrant buying a new motor (if that's the issue)

I plan on taking out the wiper stalk this weekend to clean it up and check the contacts. I'm also going to get to the wiper motor to bench test it as well. One more question, is there a technique to rule out the wiper relay as the issue?

gerlando

Well it looks like the relay for the front wipers was blown. I opened it up and took some photos as a thanks to those who offered assistance here.







Thanks again everybody

pjc

Rear wiper - I had a 'fail to return to park' issue a few months back on my '76 911 - the fuse in the engine bay had blown.

PJC

gerlando

So the plot thickens. I've replaced the relay but the wipers are still completely dead, hopefully whatever surge caused the relay to blow in the first place didn't kill the wiper motor

gerlando

This time I'm really closing the loop as my wipers are working again! I spent a bunch of time today ensuring power was getting to the wiper motors and then proceeded to take the steering wheel and column apart to get the wiper switch out to test it. Part of that process is unplugging the wiper switch from a harness under the dash. Well to my surprise the switch was already disconnected. I plugged it back in and viola, working wipers! I'm not sure how the harness came unplugged but at this point I don't care, I'm just happy to be able to drive my car again.

Phokaioglaukos

Resurrecting an old thread to address a similar, both wipers fail issue.Day one: wipers front and rear work perfectly, including the intermittent front wiper.

Day 90: While using intermittent wipers suddenly no wipe--not with intermittent **** off and turning on with the steering wheel stalk switch (not regular or fast speeds and not with pull to wash). ALSO, rear wipers will not operate.

Day 97: wipers front and rear work perfectly, including the intermittent front wiper. For about an hour. Then both front AND rear fail in parked position.

Day 98: wipers front work for about five sweeps, another partial sweep, and then fail unparked. Didn't check rear wiper before failure, but rear does not work following front wiper failure.

There are three controls for the wipers, intermittent rheostat **** and stalk for the front and rocker switch for the rear. Odd that all three fail, ‘unfair’, and fail again at the same time. There are three fuses: front wipers: luggage compartment box 3 fuse 3, luggage compartment box 1 fuse 7 (also rear wiper) and engine compartment fuse 3. All have continuity.

The only relay I have found is for the intermittent rheostat and have not tested it.

Wiggling the switch stalk has no effect. The mechanical connections on the switch stalk are known issues. I can remove the steering wheel to access the switch and clean, but I’m having a hard time figuring out why that would be the issue causing the rear wiper fails at the same time.

Other than the shared fuse #7, I cannot see why the front and rear would fail at the same time. I also do not know fuses to work intermittently. I suppose I am not understanding the wiring diagrams.

Suggestions as to how to diagnose? Clearly, I am missing something. Does the rear wiper require that its switch is on AND that the steering wheel stalk switch is ALSO on? If so, my issue may be just the stalk switch.

Phokaioglaukos

Follow up.
The single point of failure pointed to the fuse block. Fuse is good but there was corrosion on the back of the block interrupting power to both wipers. Cleaning fixed it.
Months later, same failure, but with a twist. The wiper stalk feels different when moved (the high resistance to movement and lock click is gond) and I hear a grinding noise when turning the steering wheel. Sugges that the wiber stalk switch has failed, BUT the rear wiper ALSO does not work. Old problem back again and a new one added?