83 defender Wiper Motor issues

[Flyingcatfive]

A sunshine only vehicle... This one is burning my brain.

History:
The wiper motor just stopped working two months ago. I pulled the motor and took off the cap to the brushed and found it burnt and black. Two of the three brushes were cracked. The fuse was blown too in the panel.

I ordered a new motor and put that in with ground on. Put the fuse in and hit the switch. It moved for a second than nothing. Fuse was blown. I pulled the motor and found once again cracked brushes. Drove the vehicle here and there between snow falls and noticed that the headlights were dimming on and off. Ok so electrical issue.

After looking for ground shorts etc and not finding much - I took a thorough look and cleaned up some old wiring (it's a slow project rewiring this thing on demand)

I replaced the brushes and hesitatingly hooked up the motor again (just the ground wire and harness). It came on for a second and stopped. No fuse blew. Pulled the motor and the brushes are fine. I know there is a limiter or shut off switch in there so I turned the motor/worm gear just past the click of the switch. Hooked it up and it moved about 180 degrees in 2 seconds and stopped. It's like the limiter switch kills the motor and does not reset?

I know now that i did not mark the armature's position - which will create another issue. However without hooking up the wiper drive shaft, the same thing happens. I bench tested it and the same thing happens- I can only get a bit of movement and only on one terminal. It is a two speed motor. I'm guessing that the higher speed needs power to two of the terminals at one time? Haven't tried this but not sure if it will make a difference. The steering column switch is only a few years old and has worked great all the time.

Any guesses?

Thanks!

[red90]

The switch is the park switch. You need to understand the wiring. There are three power wires coming from the wiper switch. One, when off, which sends power through the park switch, one for low speed and one for high speed. You need to follow the wiring diagram and troubleshoot the system with a volt meter.

Some of the other problems sound like a bad alternator. I would make sure that is all good as you can fry a lot of stuff with certain alternator faults.