1972 Polara 3-Speed Wiper Issues

[EllettMC]

Hey All,

Trying to track down what's gone wrong with the windshield wipers on my Polara. It's got the 3 speed wiper motor and the 3 speed switch in the dash. The wipers will stop and start on their own seemingly at random when the switch is in any position but the off position, and doesn't change speed with the switch. It also won't park the wipers, but that's a secondary concern for me. The wiring/connections seem okay from the firewall forward. I disconnected the wiper linkage to check to see if the motor was working, and it seems to rotate smoothly with no wiper arms connected.

Do y'all think it could be a bad ground in the dash? or a bad switch?

 

[Davea Lux]

Hey All,

Trying to track down what's gone wrong with the windshield wipers on my Polara. It's got the 3 speed wiper motor and the 3 speed switch in the dash. The wipers will stop and start on their own seemingly at random when the switch is in any position but the off position, and doesn't change speed with the switch. It also won't park the wipers, but that's a secondary concern for me. The wiring/connections seem okay from the firewall forward. I disconnected the wiper linkage to check to see if the motor was working, and it seems to rotate smoothly with no wiper arms connected.

Do y'all think it could be a bad ground in the dash? or a bad switch?

Sounds like the brushes in the motor are probably bad and not making good contact with the armature, especially if the wipers come on when you hit a bump in the road or tap on the motor unit. Brushes with poor contact will usually run the unit at a slow speed for a while and then the unit will stop. You can test the switch by unhooking the lead to the wiper unit, hook the test light to a good ground, probe the connector, one of the leads should have power in low switch position, one in the second position and one in the high position. If that is the case, you switch is probably working.

Dave

 

[1970cat]

do you have the three speed wiring harness? i tried to cheat by using the 3 speed motor and switch with a 2 speed harness. no good , the wipers did what they wanted when they wanted. it was like they were possessed.

 

[EllettMC]

I checked with your method Dave, looks like the switch is working. So if the brushes are bad, it's a re-build or replace scenario for the motor?

I'm not 100% certain that the wiring harness is a legit 3 speed harness, but it was working before, so it was probably the right harness.

 

[Davea Lux]

I checked with your method Dave, looks like the switch is working. So if the brushes are bad, it's a re-build or replace scenario for the motor?

I'm not 100% certain that the wiring harness is a legit 3 speed harness, but it was working before, so it was probably the right harness.

You can try putting an alligator clip on the battery positive terminal, noting which leads on the motor received power from the plug, try touching the other end of the alligator clip to one of the leads on the motor that received power, if the motor runs properly you may have a wiring issue at the bulkhead connector.

Dave