Wipers turn on after random components are shut off.

[454-k10]

I just picked up another square. It's an 82 k20 Silverado. I turn off the ac or the lights and the wipers come on for one sweep then stop.

Anyone have any thoughts why?

 

[shiftpro]

Your truck just really likes a clean windshield no doubt..

 

[chengny]

I just picked up another square. It's an 82 k20 Silverado. I turn off the ac or the lights and the wipers come on for one sweep then stop.

Anyone have any thoughts why?

Intermittent wipers?

Also - and I know it's hard to tell by observing just one sweep - does it appear that the wipers make that single sweep in HI or LO speed?

 

[Camar068]

@chengny Awesome you showed up. Curious if my thoughts of feedback due to a bad/loose ground are correct (or could even cause it lol).

 

[chengny]

@chengny Awesome you showed up. Curious if my thoughts of feedback due to a bad/loose ground are correct (or could even cause it lol).

That (improper grounding) is generally the first thing that I think of. But actually the converse would be true in this case. The common brush is always hot and the motor winding circuit is completed only when a ground connection is established through one of the two (Hi or Lo) speed brushes. So to get the motor to spin - for one sweep then go to park - would require a momentary ground fault in the ground leg of either brush.

The above, doesn't seem likely in a base (i.e. non-pulse) wiper circuit. I was thinking that since an abrupt drop in system load (caused by shutting down a heavy draw component) induces a temporary voltage spike, that spike might cause a shaky pulse module to ground the LO speed leg. That's why I asked if he has intermittent wipers.

 

[454-k10]

Intermittent wipers?

Also - and I know it's hard to tell by observing just one sweep - does it appear that the wipers make that single sweep in HI or LO speed?

My wipers have the knob you twist. I've never seen one like this. It seems to be a LO speed.

 

[454-k10]

It's this setup

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[chengny]

It's this setup

Yes, that is the switch used with intermittent wipers. Plugged into the back of the switch (with two connectors) is the pulse module:

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Switch operation:

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Switch diagnostic:

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To confirm/eliminate the module as the cause of the phantom sweeps, temporarily remove it from the circuit - and note whether the issue goes away.

Just disconnect both plugs (a 6 pin and a 3 pin) from the back of the switch and also disconnect the single (6 pin) plug that goes into the module - on the other side from the two that are hard wired.

The single (6 pin) connector - that currently goes into the module - will then need to be connected directly to the 6 pin terminal on the back of the switch. The 3 pin terminal on the switch will be unused.

If the removal of the module seems to solve the problem you can start hunting for a replacement unit - if you want. The wipers will still function as normal but they will have no delay feature.

 

[454-k10]

Yes, that is the switch used with intermittent wipers. Plugged into the back of the switch (with two connectors) is the pulse module:

You must be registered for see images attach

You must be registered for see images attach

Switch operation:

You must be registered for see images attach

Switch diagnostic:

You must be registered for see images attach

To confirm/eliminate the module as the cause of the phantom sweeps, temporarily remove it from the circuit - and note whether the issue goes away.

Just disconnect both plugs (a 6 pin and a 3 pin) from the back of the switch and also disconnect the single (6 pin) plug that goes into the module - on the other side from the two that are hard wired.

The single (6 pin) connector - that currently goes into the module - will then need to be connected directly to the 6 pin terminal on the back of the switch. The 3 pin terminal on the switch will be unused.

If the removal of the module seems to solve the problem you can start hunting for a replacement unit - if you want. The wipers will still function as normal but they will have no delay feature.

Thank you!!! I'm gonna do what you said and see if I can fix it.

 

[HotRodPC]

So how cheap did you get this truck??? Maybe they got rid of it for a reason. Have you considered an exorcism??? That'll probably fix it.

 

[Snoots]

It's this setup

You must be registered for see images attach

If it's in the position shown, that's low speed and you'll get the occasional wipe.
Move the switch to the far left and turn the knob fully counter-clockwise.

 

[454-k10]

So how cheap did you get this truck??? Maybe they got rid of it for a reason. Have you considered an exorcism??? That'll probably fix it.

$1,500. It's a 1982 k20 Silverado. Low miles and almost completely original. 4" lift. Truck is in amazing condition. It sat for a long time and needs a little work.

You must be registered for see images attach

 

[HotRodPC]

Yeah, you stole that one for that price. It's haunted and why so cheap. Get it exersized and it'll be aight !!!