78 Burban wipers not working.

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Olythekid

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Oli
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1978
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K20 Suburban
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350
Hey folks, I just bought a 78 4WD Burban and the wipers do not work. Fuse is good. As I'm waiting for a Chilton would you help me with an electrical diagram? This is what I have so far. The washer fluid pump works. Notice I am missing a connector. The wires go to the wiper motor assembly and also to this little thingy on the wheel well. Whatever that is.

What do you guys reckon?

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bucket

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The missing plug is for the washer pump that's built into the wiper motor. You have a universal washer pump added on.

Do you have delay wipers or standard wipers?
 

Charlie

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:welcome:
 

Olythekid

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Awesome, ty DvDSwan.

Bucket, don't quite know, here is picture of my wiper switch. Looks just like my 73 Firebird.

Hey Charlie, thank man. It's in a rough shape with a lot of work left . .. but I love that freaking thing. Glad to be here.

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bucket

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Boy I'd love to have a factory yellow painted 70's 4x4 Burb.

That plug on the lower part of the wiper motor will have a hot wire and then a wire for high and one for low. You can use a multi meter to test for ignition power at the yellowish wire and then test to make sure the wiper switch grounds out the other two wires. Obviously not at the same time, one for high and then low. If it tests out ok, you can assume the wiper motor is dead.

Or you can put the wipers on high and then smack the wiper motor with a ball peen hammer. If the wipers start to work, that will tell you the motor is shot also.
 

Snoots

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Nice 'Burb!

Looks like some monkeys have been into the wiper wiring already. Hard to tell for sure at this distance.
bucket has a good idea I'd follow and GMSB has a magnificent schematics area.
Check for a good ground from the wiper motor to the frame/body too.

Welcome from Georgia
 

Olythekid

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I went to play with it a bit.

Plugged the bat straight to the motor's yellowish wire receptacle and ground to the frame one of the other terminal and the wiper moved.
I do have 12V at the yellowish wire plug.
Wiper motor does not work when bat straight to the motor's yellowish wire receptacle and ground to either of the PLUG.
I do have 12V on each side of the circuit breaker.
On the wiper switch itself I have 12V on terminals C, D and F.
It seems C and D had a little love affair. Maybe the inside of the switch is jacked. More testing tomorrow when it gets 'warmer' again. :)
 

Olythekid

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New switch it was. When I opened the old one up, the plastic has melted on the C and D metal strips preventing them to make proper contact with the plug. I wonder how it shorted in the first place. Hopefully and one time fluke.
 

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