Help with 3spd wipers

[valkman]

I just bought a 73 Challenger with 3spd wipers. The wipers work, but they don't go back to park? What should I be looking for? The harness is new, but the switch and the motor not.

 

[Adam]

There is a trouble shooting guide in the service manual.. should be easy to find. Dirty contacts are common.

 

[Steve340]

Evidently the switch and the motor must be well grounded or in other words earthed.
Pretty easy to try.

 

[quapman]

Check the brass ground strap as Steve340 suggests and if that doesn't work, it's the contacts inside the plate where the two tabs stick out and have wires soldered to them. They commonly go bad. You have a pic of the motor?

 

[valkman]

I found this youtube video https://www.google.com/url?sa=t&sou...CCowBQ&usg=AFQjCNHqqolYcCpdQhLvMy2ujYmCEf-0gQ
That shows what happens with a bad ground, I have to take another look. Thanks everybody for your help

 

[valkman]

So tested the motor per the service mannual, and it tested good. I checked the connections under dash, and added an additional ground to the switch housing, and still no change. I'm assuming the switch is bad.

 

[Slotts]

Sorry, let's try this again on the next post. The centering was all over the map...

 

[Slotts]

You really need to isolate the motor from the switch to know exactly what the issue is. The wiper motor can be tested while still mounted on the firewall. This is a cut and paste from a white paper I wrote on how to test the motor. It is best down with alligator clip leads and insulated boots over the clips. Radio Shack has what you would need. (Did I just write Radio Shack???)

Three Speed Wiper Motor Bench or Firewall Four Wire Terminal Test:

Forward (Slow)
12V+ to Red & Brown
Green to Motor Ground Strap
12V- to Motor Ground Strap

Forward (Fast)
12V+ to Brown
Green to Motor Ground Strap
12V- to Motor Ground Strap
Red Not Connected

Reverse (Park)
12V+ to Blue
Green to Brown
Red to Motor Ground Strap
12V- to Motor Ground Strap

Note: If the motor does not move forward initially, try the reverse test, once. If the motor returns to the park position and stops, continue with testing the forward motion. The motor will not move forward if the last power applied was moving the motor in reverse and did not complete the park motion.

Give that a try and see what happens with park. If the motor doesn't park after testing like this, the park disconnect arm may be not making contact inside the gear box cover.

Jim

 

[valkman]

I tested the motor using the troubleshooting in the service manual: green to ground; brown and red to positive the motor would run (with red removed from positive I got it to run in 2 speeds). By jumping the green and brown and grounding the red and blue to positive it went to park . I checked the ground at the fire and under the dash (by adding a test ground wire) and it still only goes 1 speed and doesn't go to park with everything connected normally. My question is could it be anything else but the switch and can it be tested?

 

[Slotts]

Sure the switch can be tested. What is the part number on the wiper switch? Two speed wiper switches and three speed wiper motors do not play nice together. Same the other way three speed or variable do not work with a two speed motor.

Jim

 

[valkman]

The is 4 position switch: off, 1, 2 ,3. It also has a washer function

 

[Slotts]

Ok, good! It sounds like you have a 3488764 three speed switch. In the off position on the switch, test the impedance between the B and P terminals. That should read 0 Ohms. The second test is between F1 and the metal frame of the switch. That too should read 0 Ohms. If both of those tests read correctly, then test the impedance between the switch socket and the bulkhead connector:

Bulkhead position 1 - Switch Socket A (Brown w/ White Tracer)
Bulkhead position 2 - Switch Socket F1 (Red)
Bulkhead position 5 - Switch Socket P (Blue)
Bulkhead position 6 - Switch Socket F2 (Green)

Each of these reading should show 0 Ohms.

Jim

 

[valkman]

Thanks Jim!

 

[jeffv21]

So I checked my wiper motor this way. Forward ok but just sparks when I touch wire when I try reverse. Not the motor , my connection.

 

[valkman]

Sound's like it's might be grounding, check your wires.