Weird electrical - windshieldwasher problem - ideas??

jmackro

jmackro

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About a week ago, I posted a message asking about sources for the turnsignal/windshieldwasher switch used on early Coupes. My wipers wouldn't shut off and when I thought I had them off, they would come on unexpectedly as I was driving. The knob at the end of the stalk felt loose, so I figured I needed to replace the switch.

I found one on ebay for $19.95 that was advertised as being off a Bavaria, and that looked pretty new. Got it, installed it, figured I was finished. HA!

The new switch has a much better "feel" - the windshieldwiper function really clicks on and off. However, when I took the Coupe out today, after about 1/2 mile, the ^&%$#$ wipers came on again - they will run for 2-3 cycles, and then go off - almost like intermittant wipers on "random" setting.

OK, I know the punch line is going to be: "Buy that $17.95 wiring diagram from the guy on ebay". Sure, I'm happy to do that. But, can anyone figure out where in the Coupe's ww circuit there might be something that could energize the motor BESIDES the switch on the column? I figured out where the ww relay is (above the hood latch handle), and tried wiggling that, but couldn't induce the fault with the car standing still. Ditto for rapping on the ww motor.

I can't believe that both my old switch and the new one would exhibit the same fault. I guess one diagnostic will be to unplug the switch's connector (located right above the steering column), and see if I still get the random operation.

Anyone else been here before?
 
The wiring diagram seems to show that the wiper motor
kicks in in two cases: 1) closing the wiper switch supplies 12V
over a black wire, 2) activating the washer supplies ground
over a brown-black wire into pin 85 of the relay.

If your activation is brief, it may be a clue that that ground
circuit gets closed and the relay believes the washer
pump was just activated. I would see if that pin can be
isolated on the relay side (maybe bend the pin or unplug the
cable).
 
more suggestion

I want to take Arde's good advice a little further.

His second paragraph appears to suggest that a ground is occurring when it shouldn't. I add that this ground could occur anywhere over the path of that ground wire, thus simply disconnecting it at one end may not stop the brief WW occurrence. One likely location is where the wire passes through the firewall, or very close to the end where an almost-disconnected wire may be drooping onto something conductive.

Try locating the wires for the circuit. Then, ignition on or car running, reach down and wiggle the wires to simulate the initiating event. Clearly (to me anyway) it's not the switch that's the problem. I think it's along a wire path somewhere.

Sussing out wiring diagrams can be a real b*tch, I was doing it last weekend to attempt to resolve a "cranks and starts but won't run" problem. Turns out I had simply knocked off one connector on the starter solenoid. But before noticing it, I stared at the diagrams for 45 minutes. Unproductively.

But keep us posted on how this works out.
 
There is one more possibility for the wiper to turn on by itself, and that
would be a faulty switch inside the wiper motor (the switch that powers
the motor so that the arms rest in their horizontal position).

The diagnosis would as follows:

- Unplug pin 85 from wiper relay (black wire), if problem persists
it is a ground path artificially created. The path cannot be too solid
or you would also have the washer pump activate (assuming the pump
is still there).

- Unplug just pin F (brown-black wire) from relay, if problem persists
it would be a bad switch inside the motor.
 
Thanks for the suggestions. I think we are on the right track.

I performed some more diagnostics today - first, unplugged the connector from the ww/ts switch - that made no difference - wipers still come on intermittantly. So, I guess that proves that I don't have a second defective switch.

Next I just unplugged the ww relay - well, then the ww circuit was just completely dead - no surprise there. Unfortunately, the individual wires into the connector that the relay plugs into are hard to access - it's all stuffed up above the hood latch/beneath the dash. But, I guess that's where I gotta work.

My washer motor is frozen, and I really have no need for functional washers. So, I would gladly disable that circuit if it solves my problem.

I am guessing that the WW motor is NOT the problem - I can feel the relay click when the wipers come on (though I have not yet found the place to wiggle the harness to initiate this). Also, the motor seems to run for a set # of cycles - if it were something internal to the motor, I would expect it to come on, and stay on.

Any possibility that the relay could be defective? That is, instead of a ground in the wiring somewhere it is internal to the relay?

One other clue: I can turn on the ignition, and wiggle wires all day, but not initiate the fault. However, once I start the engine, the wipers come on pretty quickly. It could just be the vibration created by the running engine causing the short to make contact. Any other reasons why a running engine would cause this problem (say, higher voltage with the alternator turning?).

Thanks again for all of the ideas.
 
wierd electric?

Well, after 30 years of storage I powered up my car (electric) . removed all fuses and connect to battery. No 1 fuse inserted and suddenly powered roof was moving (number 10 fuse...) Same for windshield viper, also moving though according to spec fuse was not inserted. I true believe that every car is individual in electrial.
 
A-hah!

you said the wiper motor activates for a set number of cycles - that is characteristic of what's supposed to happen when you run the washer pump. (maybe you knew that).

So I'd look into the WW intermittent relay. Somehow it thinks you've held the washer on for a few seconds.
 
Yes, the washer pump theory is looking better.
The grounding could be occurring at the washer pump itself,
and that would explain why engine vibration causes it but
jiggling wires does. You could unplug both wires from the
pump and see if it persists, or just remove the pump and wires
altogether.
 
Arde:

Oh, I tried disconnecting the washer pump motor - it made no difference. I tried grounding the brown wire that goes to the pump (which I would think already is grounded) - again, it had no effect.

My guess is that the problem is between the column-mounted switch and the relay. That relay seems to control the entire windshield wiper system. Perhaps I can disable just the washer function by disconnecting the wire from terminal #85 or F as you suggested in an earlier message.

Fortunately, it isn't going to rain again until October, so I just pulled the WW fuse - I've got all summer to solve this problem.
 
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