An electrical window question for the techy types

[carson]

I am going nuts trying to figure why my electric windows will not work on my 81 SC. I have tried changing the relay and the fuse is fine. Looking at the relay with the power off I get 12 volts at pin 30, zero volts at 86 and also a ground, zero volts at 87 and no ground, at 85 I get a ground as expected. With the ignition in the run position I get 12 volts at pin 30, 12 volts at pin 86, zero volts at 87 and a ground, at 85 I get a ground as expected. WASSSS up. Can anybody tell me what is wrong with this picture before I fill the car with dirt and plant flowers in it?

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Eric Busche
81 Targa

[Panic Attack]

Try a switch, they go out alot.

[Early_S_Man]

Eric,

In the second part of your test/measurement scenario above ... unless there is something wrong with the relay, such as an open coil between pins 85 and 86 (should measure typically between 70 and 100 Ohms) or a faulty contact ... you SHOULD have continuity between pins 30 and 87, and hence, also 12 Volts at pin 87 as well! I have to assume the 'ground' you measured at pin 87 was through the motor windings.
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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 06-26-2001).]

[GIBSON]

Eric, as Warren said, check continuity on all circuits. Mine had a problems with the grounds on the passenger side door. I was able to isolate the problem by doing continuity checks, the ground had become loose inside the door at the connector bar.

Bruce Herrmann
73911S

[wellsmokey]

A Bosch relay works as follows:
at rest, pins 30 and 87 should not have continuity. pins 30 and 87a should. when the relay is triggered, pins 30 and 87 should have continuity. thus, when the relay is triggered, 12v is transferred from pin 30 to 87. The way the relay is triggered is through pins 85 and 86. If pin 85 has constant ground, than pin 86 should receive 12v (from the ignition switch) to trigger; or vice versa, if pin 86 has constant ground, than pin 85 should have 12v (from the ignition switch) to trigger. The way to check it is to listen for it to click when you turn the key.
The best way to check if you are getting power to the motor is directly at the motor. Thus removing your door panel and using a test light directly at the motor. Bosch relays are very reliable, but may have corosion.

[rstoll]

Check the spade connectors on the motors themselves. Any moisture in the door will corrode the motor connections. Clean up the motor terminals and replace the connectors.

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Robert Stoll
83 SC
83 944