Wiper electrics

[cj847]

I am trying to figure out my wipers on my 66 c10.

I have tested the motor independent of wiring and it is good.
I tested the switch and it is good.
I tested the wiring between the two and it is good.

Not sure what is wrong, but the motor will occasionally run via the switch then quit.

Just to check my understanding of the wiring- The yellow wire brings power from the fusebox, the light blue wire provides ground via the switch. And the dark blue wire provides ground for the squirter.

What am I missing? I tried wiggling the switch to see if it was intermittent but it didn't affect anything.

[PGSigns]

The switch needs to have a good ground. If it is not getting it from the contact with the bezel and the bezel is not grounded good to the dash they wont work. I recently went through this and had a switch that had to high a resistance to ground in the switch. Chased grounds for a while and setting on my meter compounded the issue. What I thought was 1 ohm was 1K ohms.
Jimmy

[cj847]

Yes, I was curious about that. There is a ground attached to the switch but for some reason it still has to ground to the dash.

[ray_mcavoy]

Originally Posted by cj847

There is a ground attached to the switch but for some reason it still has to ground to the dash.

If you're referring to the black wire connected to the switch, that is a switched ground for low speed, not a constant ground wire for the switch.

With the switch in the low speed position, it should connect both the black and light blue wires to ground (via the switch case attached to the metal dash). For high speed operation, the switch only grounds the light blue wire.

[cj847]

Thanks to both of you. It is starting to make sense now. I repainted my bezel-I guess i need to go back and sand a bare spot for better connection.

[PGSigns]

I put a star washer on mine the last time I put it in. Slid it over the switch so it gets a good ground to the back of the bezel.
Jimmy

[bigmoe]

There's a small built in copper ground strap right on the motor assembly at one of the mounting bolts. They corrode and break. I drilled a hole on the bracket and added a ground wire to run to ground.

[ray_mcavoy]

Originally Posted by bigmoe

There's a small built in copper ground strap right on the motor assembly at one of the mounting bolts. They corrode and break. I drilled a hole on the bracket and added a ground wire to run to ground.

Yes, that is the ground for the parking switch inside the motor assembly. The wiper motor should still run normally on high & low speed via the ground provided by the dash switch even if that ground strap on the motor is bad/missing. But without that ground, the parking feature won't work correctly. The blades will just stop instantly when the dash switch is turned off instead of continuing to run through the cycle and stop at the base of the windshield.