Help!!! Wiper Motor smoke

[schoeassoc]

We just finished our total restoration of the 79. We're having a problem with our wiper system. We have a new switch, wiring harness and motor. We have all the electrical connectors hooked up correctly. ( Good ground ). When we turn on the switch nothing happens EXCEPT smoke from the motor right at the 3 part connector. We thought maybe we got a bad motor so this is the second one.
Since everything is new why won't it work??? Help!!
Has anyone had a similar problem? We don't want to see our car go up in smoke.
Can we be getting to much voltage into the wiper system from our new battery?
All you electrical experts give us some tests to troubleshoot the system. Thanks. Bill

 

[sac001]

I think you need to check the voltage at the motor first. Check voltage at each leg coming into the motor. You should only get 12 volts on one leg at a time. (Do this quickly, by the way.) If you are only getting 12 volts, disconnect the wiper arms and see if the motor turns. It is possible that the wiper arms are stuck in place and won't let the motor move, thus causing the smoke.

Good luck!
Steve

 

[schoeassoc]

The wipers are not attached at all. We first wanted to see if the motor worked. We'll check the voltage. If it's more than 12volts whats the solution. Thanks for the input. Bill

 

[69MyWay]

There is a resister/capacitor on the plug right where it goes into the wiper motor. It prevents the backfeeding of the ground signal. Otherwise, it will smoke and do all kinds of thing if it is bad, broken, missing, or even twisted where the legs are making contact.

 

[vigman]

Chris... that's a Diode ( Wiper Motor )..

It's like a one way valve...
Now I do not have a schematic for a 79, a partial on an 81 is as close as I get.

Pointers to the right direction...( best guess)

However if it's like an 84 setup you must pull in the control line for the PARK RELAY!
( making the line go to +12 volts) to clear the mechanical arm which parks (read LOCKS) the motor drive shaft in position..

If you do not activate that line, the mechanical arm will not come OFF the motor shaft, will hold it in position and act as a smoke generator.


The Black line is frame ground

and I'm guessing( BIG TIME ) the PINK line needs to be HOT before any of the other MOTOR lines get hot.

So remember this is just a theory... but worth investigation... and an 81 ALSO has a module under the dash which is the intermittant wiper controller assy!


Vig!