I have two wiper motors on the bench. I can't figure out how to test them. There are two leads (that I can see) that come off the motor. One goes to the underside of the 3 prong connector. The other (red) was just taped up. Where can I apply power to check the motor - I am assuming both of these leads may be positive???

 

what year motor?
Is the motor mounted to the wiper housing or is the motor separated from the housing?
If you have it in the housing do you have the three prong connector that manages the start/stop relay connected?

If the motor is separate then the two leads are both for +12 and the motor case is ground. One of the +12 wires is for low speed then both together give you high speed.

If the motor is in the wiper housing and you've connected the start stop relay then you can test the motor and the relay like this:

Mount the housing on your bench vice (so the assembly doesn't move)

Ground the vice/wiper housing to your +12 power source (I simply run jumper cables to the car battery and clamp the ground to the vice). You can then connect the hot side of your +12 source to the single red wire coming from the housing. This gets you power to the motor.

Now simply put +12 volts across the relay as well (there are the two wires in the three prong connector that run to the relay which allow the switch to open an capture/release the spall from the gear). The third wire in the connector is the other hot wire (high speed - see above comment) running directly to the motor. If you put +12 to it while the motor is running you'll get high wiper speed.)

Once you have the motor grounded and the +12 attached to the red wire you can then turn on/off the wiper motor using the relay (either side of the relay can be hot/ground as it simply opens and closes the switch (the main switch is inside the green colored assembly) for the main red wire). This is a easy way to bench test your rebuild prior to putting it back into the car.

 

Thanks for very good info. Car is a 78. The replacement motor year is unknown..but they both are one piece that bolt to the upper firewall with three bolts/studs

 

I agree with Hammer Head, i just did this on my '76. Mine i sthe type with the washerfluid "pump" built into the motor assembly. Be careful if you take it apart as there are a couple of little springs in there. That's the reason I took mine apart-I could here something moving around in there. Regreased the worm gear cleaned everything up and back in business. You can also use a battery charger to check the motor, it won't turn as fast but it is enough to let you know if it works or not.

ltlevil