Help, strange wiper issue. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Thealien** · 08-08-2021, 12:28 PM

I have been slowly getting things working on the Blazer. This morning I swapped out the AC heat control as it looked bad and a couple of the levers and blower switch were broken. I got that in and then started working on the hack job where the radio goes. I cleaned it up and have the single din installation cage in and slid the radio in.

I was careful and do not believe I pinched any wires but now any time I have the ignition on or the Blazer running the wipers are on all the time. I even pulled the wires off the wiper switch and they were still on? They have been working fine up until today. Since it still does it with the switch wires unplugged I do not believe it to be the switch. I pulled the fuse for now!

Any ideas?

Thanks
Mark

**LockDoc** · 08-08-2021, 01:26 PM

Quote:

Originally Posted by Thealien

I have been slowly getting things working on the Blazer. This morning I swapped out the AC heat control as it looked bad and a couple of the levers and blower switch were broken. I got that in and then started working on the hack job where the radio goes. I cleaned it up and have the single din installation cage in and slid the radio in.

I was careful and do not believe I pinched any wires but now any time I have the ignition on or the Blazer running the wipers are on all the time. I even pulled the wires off the wiper switch and they were still on? They have been working fine up until today. Since it still does it with the switch wires unplugged I do not believe it to be the switch. I pulled the fuse for now!

Any ideas?

Thanks
Mark

Can you tell if they are running on high speed or low speed?

LockDoc

body bolt · 08-08-2021, 02:37 PM

The wires you pulled off were likely for the washer.

**Thealien** · 08-08-2021, 03:33 PM

Quote:

Originally Posted by body bolt

The wires you pulled off were likely for the washer.

I believe there are only three wires on the wiper switch. And those are what I pulled off.

**Thealien** · 08-08-2021, 03:34 PM

Quote:

Originally Posted by LockDoc

Can you tell if they are running on high speed or low speed?

LockDoc

I want to say hi but I am not 100% sure. Is there a thread anywhere of some testing I can do?

**LockDoc** · 08-08-2021, 04:24 PM

Quote:

Originally Posted by Thealien

I want to say hi but I am not 100% sure. Is there a thread anywhere of some testing I can do?

Yes, scroll down to the 2 speed wiper section.

http://67-72chevytrucks.com/vboard/s...d.php?t=413551

LockDoc

**Thealien** · 08-08-2021, 05:09 PM

Quote:

Originally Posted by LockDoc

Yes, scroll down to the 2 speed wiper section.

http://67-72chevytrucks.com/vboard/s...d.php?t=413551

LockDoc

I just read that whole thread. I had subscribed and posted in it once?

Not ready to pull the motor out yet, pulled the fuse for now. I have lots of projects to do already. If I haven't found a wiring issue the cowl is coming off eventually. I would probably pull the motor then if I think I have to.

**Sheepdip** · 08-08-2021, 05:25 PM

I'm not saying this is your problem but you may have a "Ground" going to a "Positive" somewhere and it's worth checking out.

In the early 80's I bought a 1970 LT1 Corvette to restore, it was drivable but when I would hit a bump, or sometimes for no reason that I could blame it on, the radio would play when off and/or the wipers would cycle.

I did not get to excited about it as I only drove the car 3 or 4 times for about 2 weeks before I tore it down.

While stripping the car down and pulling the wiring harness I tagged and marked where everything went to and was disconnected from for future reference if need be.

A corvette since it is fiberglass/plastic has a dedicated ground for everything, long story short when installing the new harness I discovered the dedicated ground for all of the dash component's attaches to the bell housing bolt just behind the starter motor, the ground lead/wire that I removed was attached to the main positive post on the starter solenoid.
Someone evidently changed the starter and forgot where those wires were supposed to be connected, and the positive post seemed like a good spot to connect the ground wire.

Wrenchbender Ret · 08-08-2021, 07:48 PM

The wipers have a hot lead going to the motor all the time. The switch grounds the motor to turn it on. Your ground wire from the motor is grounded somehow. Or the motor is shorted internally. Or the wipers are not parking & keep trying to park. If you are running the motor without the arms or blades this can happen as without any drag the linkage coasts on by the park & the motor keeps making attemps to park.
George

**Thealien** · 08-09-2021, 06:33 AM

Quote:

Originally Posted by Wrenchbender Ret

The wipers have a hot lead going to the motor all the time. The switch grounds the motor to turn it on. Your ground wire from the motor is grounded somehow. Or the motor is shorted internally. Or the wipers are not parking & keep trying to park. If you are running the motor without the arms or blades this can happen as without any drag the linkage coasts on by the park & the motor keeps making attemps to park.
George

I believe it is shorted internally or externally. I guess it could also just be a coincidence that the wiper motor went bad while I was working on something else? The wiper arms and blades are on and I was not having an issue with park prior to this?

Tomchev · 08-09-2021, 06:46 AM

You have one of the wires grounded.

**pjmoreland** · 08-09-2021, 11:37 AM

I'm not super familiar with the wiper motor wiring, but it appears that the yellow wire provides the 12V, and then either the light blue or black wire provides the ground to complete the circuit depending on whether the switch is on high or low. These wires go to the black plastic connectors on the motor (the brown connector is for the washer pump). You could try unplugging the black wire to see if the motor stops. If it does stop, then the black wire is shorted out somewhere. If it doesn't stop, then you could pop the light blue wire out of the housing and leave the yellow wire connected. If the motor stops, then the light blue wire is shorted somewhere. If it doesn't stop with both the black and light blue wires disconnected, then you probably have an internal short in the motor. There's a photo in this post that shows the locations of the wires.

http://67-72chevytrucks.com/vboard/s...d.php?t=771139

**YellowK5** · 08-09-2021, 02:42 PM

It sounds like the parking contacts in the motor are stuck. it will run then stop when it gets to the wiper arm park position normally.
Wrench Bender may be on to it..

08-08-2021, 12:28 PM	#1
Thealien Senior Member Join Date: Jun 2007 Location: Pine Ridge Florida Posts: 4,134	Help, strange wiper issue. I have been slowly getting things working on the Blazer. This morning I swapped out the AC heat control as it looked bad and a couple of the levers and blower switch were broken. I got that in and then started working on the hack job where the radio goes. I cleaned it up and have the single din installation cage in and slid the radio in. I was careful and do not believe I pinched any wires but now any time I have the ignition on or the Blazer running the wipers are on all the time. I even pulled the wires off the wiper switch and they were still on? They have been working fine up until today. Since it still does it with the switch wires unplugged I do not believe it to be the switch. I pulled the fuse for now! Any ideas? Thanks Mark __________________ Click on my Not really a build thread, yet NOT SO RUST FREE RUST FREE BLAZER LS ENGINE SWAP INFORMATION THREAD BOLT RESTORATIONS 4l60 to an NP205

08-08-2021, 02:37 PM	#3
body bolt Registered User Join Date: Oct 2020 Location: Albuquerque, New Mexico Posts: 474	Re: Help, strange wiper issue. The wires you pulled off were likely for the washer.

08-08-2021, 05:25 PM	#8
Sheepdip Senior Member Join Date: Nov 2018 Location: Waterford California Posts: 2,626	Re: Help, strange wiper issue. I'm not saying this is your problem but you may have a "Ground" going to a "Positive" somewhere and it's worth checking out. In the early 80's I bought a 1970 LT1 Corvette to restore, it was drivable but when I would hit a bump, or sometimes for no reason that I could blame it on, the radio would play when off and/or the wipers would cycle. I did not get to excited about it as I only drove the car 3 or 4 times for about 2 weeks before I tore it down. While stripping the car down and pulling the wiring harness I tagged and marked where everything went to and was disconnected from for future reference if need be. A corvette since it is fiberglass/plastic has a dedicated ground for everything, long story short when installing the new harness I discovered the dedicated ground for all of the dash component's attaches to the bell housing bolt just behind the starter motor, the ground lead/wire that I removed was attached to the main positive post on the starter solenoid. Someone evidently changed the starter and forgot where those wires were supposed to be connected, and the positive post seemed like a good spot to connect the ground wire.

08-08-2021, 07:48 PM	#9
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,229	Re: Help, strange wiper issue. The wipers have a hot lead going to the motor all the time. The switch grounds the motor to turn it on. Your ground wire from the motor is grounded somehow. Or the motor is shorted internally. Or the wipers are not parking & keep trying to park. If you are running the motor without the arms or blades this can happen as without any drag the linkage coasts on by the park & the motor keeps making attemps to park. George Last edited by Wrenchbender Ret; 08-08-2021 at 07:55 PM.

08-09-2021, 06:46 AM	#11
Tomchev Registered User Join Date: Jan 2016 Location: Forest City NC Posts: 30	Re: Help, strange wiper issue. You have one of the wires grounded.

08-09-2021, 11:37 AM	#12
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,981	Re: Help, strange wiper issue. I'm not super familiar with the wiper motor wiring, but it appears that the yellow wire provides the 12V, and then either the light blue or black wire provides the ground to complete the circuit depending on whether the switch is on high or low. These wires go to the black plastic connectors on the motor (the brown connector is for the washer pump). You could try unplugging the black wire to see if the motor stops. If it does stop, then the black wire is shorted out somewhere. If it doesn't stop, then you could pop the light blue wire out of the housing and leave the yellow wire connected. If the motor stops, then the light blue wire is shorted somewhere. If it doesn't stop with both the black and light blue wires disconnected, then you probably have an internal short in the motor. There's a photo in this post that shows the locations of the wires. http://67-72chevytrucks.com/vboard/s...d.php?t=771139

08-09-2021, 02:42 PM	#13
YellowK5 Active Member Join Date: Jun 2021 Location: Rancho Cucamonga California Posts: 170	Re: Help, strange wiper issue. It sounds like the parking contacts in the motor are stuck. it will run then stop when it gets to the wiper arm park position normally. Wrench Bender may be on to it..

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