Storm is a coming ~ Wiper motor help please

[Rusty Scout]

Its for my Scout II. This is the 3rd wiper motor in a few years. The rotten windshield frame is not helping the situation much I am sure. I am just wondering what are the common problems with these motors. Is it internal corrosion, burnt windings, does the switch on the dash fail?, bad ground causing a short, bad relay...?

Lately nothing happens when I turn on the wipers except for the ammeter drops slightly. Sometimes I can get some movement if I help the arms along or tap on the motor. Any suggestions??

[Rusty Scout]

deep into the wiper motor threads I found this about how it is wired:

Scout wiper motor,

It is a three wire motor with the common being the internal ground.

The wires to and from the Scout switch are:

82 +12 hot

82A +12 after going through breaker, feeds the park switch on the wipers, ( Green wire on Wiper plug) and hot into the switch.

82 B feeds high speed on the wipers, ( Black wire on wiper plug.)

82 C feeds low speed on wipers, (Red wire on wiper plug. )

A 187 goes to washer motor, on this setup, I have here, it`s a green wire, the rest of the wires are black..

The Scout switch in low speed position closes the circuit from 82 A to both 82 B and 82 C wires,

In high speed it closes the circuit from 82 A to 82 B only.





How do you get 2 speeds out of that?

Anyway I will post a follow up on how I solve the problem.

[Paul "Misterfixit" Schulz]

yes there is an internal ground but that only has the function of self park, the low and high speeds are grounded to operate via the wiper switch then when turned to the off position the low speed wire is connect to the self park wire and grounded via the park contact in the wiper motor.

[ruderunner]

The multiple motor failures point towards something else being the problem. Check for frozen/binding linkage, especially the wiper pivots. Also running a separate ground from the motor case to the body helps, lots of times the ground path through the motor mounts isn't very good and gets fixed accidentaly during motor replacement.

[Ronmc1954]

I think replaced my wiper motor 3 times before I found a bad connection on the bulkhead connector.

Ron

[Eric VanBuren]

Originally Posted by Rusty Scout

deep into the wiper motor threads I found this about how it is wired:

Scout wiper motor,

It is a three wire motor with the common being the internal ground.

The wires to and from the Scout switch are:

82 +12 hot

82A +12 after going through breaker, feeds the park switch on the wipers, ( Green wire on Wiper plug) and hot into the switch.

82 B feeds high speed on the wipers, ( Black wire on wiper plug.)

82 C feeds low speed on wipers, (Red wire on wiper plug. )

A 187 goes to washer motor, on this setup, I have here, it`s a green wire, the rest of the wires are black..

The Scout switch in low speed position closes the circuit from 82 A to both 82 B and 82 C wires,

In high speed it closes the circuit from 82 A to 82 B only.





How do you get 2 speeds out of that?

Anyway I will post a follow up on how I solve the problem.

The way the slow speed is achieved is by a "bucking" coil. Circ 82B is connected to a standard motor winding. Circ 82C goes to a winding that counteracts the magnetic field to slow the motor down. That is why low speed needs power on 2 wires and why circ 82C by itself won't make the motor work.

Like Ron said check the connection at the BHC. Since the windshield frame is that rusty you might consider adding a ground wire under one of the mounting bolts and run it to a good ground.

[Paul "Misterfixit" Schulz]

Originally Posted by Eric VanBuren

The way the slow speed is achieved is by a "bucking" coil. Circ 82B is connected to a standard motor winding. Circ 82C goes to a winding that counteracts the magnetic field to slow the motor down. That is why low speed needs power on 2 wires and why circ 82C by itself won't make the motor work.

Like Ron said check the connection at the BHC. Since the windshield frame is that rusty you might consider adding a ground wire under one of the mounting bolts and run it to a good ground.

Actually the low speed is achieved by putting power through the brushes at 180 degrees to each other, high speed is achieved by shortening the current path and therefore increasing the current flow through the armature by supplying one brush at about 45 degrees off set making the angle around 135 degrees across the armature.

[fredsterra]

I had an issue with mine a few years ago when I installed a delay wiper switch. (If you don't have one get one! My .02)

I couldn't get mine to work on low after I installed the switch. So after several attempts. I took off the back cover and used 2 cans of CRC Electric Parts Cleaner. Reinstalled and works like a charm! I guess it had 30 years of crap inside the motor? But it worked.

[Scott H]

I had this problem on a beater a few years ago. Sounds like it's getting water(rusty frame too) in side the motor. I pulled the motor and pulled it apart and cleaned it out inside. Then reassembled it using silcone to seal up the motor end plates. Worked until I sold it 4 years later and as far as I know the next owner had no problems with it over the next year.
Scott

Originally Posted by Rusty Scout

Its for my Scout II. This is the 3rd wiper motor in a few years. The rotten windshield frame is not helping the situation much I am sure. I am just wondering what are the common problems with these motors. Is it internal corrosion, burnt windings, does the switch on the dash fail?, bad ground causing a short, bad relay...?

Lately nothing happens when I turn on the wipers except for the ammeter drops slightly. Sometimes I can get some movement if I help the arms along or tap on the motor. Any suggestions??

[Rusty Scout]

Thanks everyone at least now I know how to bench test this thing now. I am going to go back to motor #2 and get her running on the bench and add a little silicon to seal it since she is exposed to water.