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Wipers pulsing? [message #271345] Sat, 07 February 2015 07:08 Go to next message
Larry is currently offline  Larry   United States
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
Senior Member
This happened 2 yrs ago at my daughters house in Jacksonville. Wake up in the middle of the night and the Henderson wiper kit is pulsing about every 45 seconds or so. WTF??? I pulled the fuse for now, because we have to go to grandson's Pinewood Durby today. Can't remember what I did to fix it...any ideas why this is happening? Switch is off and intermittent is set to as infrequent as possible. Ken....you out there?

Larry Smile
78 Royale w/500 Caddy
Menomonie, WI.
Re: [GMCnet] Wipers pulsing? [message #271348 is a reply to message #271345] Sat, 07 February 2015 07:31 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
Larry,

If you mentioned the prior incident, I've forgotten it, so I consider this
the first time I've heard of such.

Has it been raining there, or have you recently been in rain?

The intermittent sweep is controlled by a part of the PC board in the
motor. The sweep delay is set by an RC time constant where the
R(esistance) is the 500k Ohm sweep delay rheostat plus an in-line 680 Ohm
fixed resistor. If moisture gets into the Weather Pak connector on the
motor, or into the back of the motor covered by the black plastic plate, it
could reduce the R in the RC, perhaps far enough to trigger the sweep
circuit. Since the motor is continuously powered from the BATTery (to
enable the blades to park regardless of the position of the IGNition
switch), it can run at any time.

The remote possibility of what you're experiencing can be eliminated by
moving the long white wire from a BATT connection to an IGN source.

That's my best WAG. :-)

Ken H.


On Sat, Feb 7, 2015 at 8:08 AM, Larry wrote:

> This happened 2 yrs ago at my daughters house in Jacksonville. Wake up in
> the middle of the night and the Henderson wiper kit is pulsing about every
> 45 seconds or so. WTF??? I pulled the fuse for now, because we have to
> go to grandson's Pinewood Durby today. Can't remember what I did to fix
> it...any ideas why this is happening? Switch is off and intermittent is
> set to as infrequent as possible. Ken....you out there?
> --
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: Wipers pulsing? [message #271351 is a reply to message #271345] Sat, 07 February 2015 10:19 Go to previous messageGo to next message
rjw   United States
Messages: 697
Registered: September 2005
Karma: 4
Senior Member
Larry wrote on Sat, 07 February 2015 08:08
This happened 2 yrs ago at my daughters house in Jacksonville. Wake up in the middle of the night and the Henderson wiper kit is pulsing about every 45 seconds or so. WTF??? I pulled the fuse for now, because we have to go to grandson's Pinewood Durby today. Can't remember what I did to fix it...any ideas why this is happening? Switch is off and intermittent is set to as infrequent as possible. Ken....you out there?

The same thing happened to me a few years ago. While driving in dry weather, the electric wipers would just come on. The temporary fix was to pull the fuse as you did. The permanent fix (I hope) was the installation of a new (rebuilt from Autozone with lifetime warranty) wiper motor.


Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com

Roller Cam 455, TBI+EBL, 3.42 FD, 4 Bag, Macerator, Lenzi (brakes, vacuum system, front end stuff), Manny Tranny, vacuum step, Tankless + OEM water heaters.
Re: [GMCnet] Wipers pulsing? [message #271362 is a reply to message #271348] Sat, 07 February 2015 12:08 Go to previous messageGo to next message
Larry is currently offline  Larry   United States
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
Senior Member
Ken Henderson wrote on Sat, 07 February 2015 07:31
Larry,

If you mentioned the prior incident, I've forgotten it, so I consider this
the first time I've heard of such.

Has it been raining there, or have you recently been in rain?

The intermittent sweep is controlled by a part of the PC board in the
motor. The sweep delay is set by an RC time constant where the
R(esistance) is the 500k Ohm sweep delay rheostat plus an in-line 680 Ohm
fixed resistor. If moisture gets into the Weather Pak connector on the
motor, or into the back of the motor covered by the black plastic plate, it
could reduce the R in the RC, perhaps far enough to trigger the sweep
circuit. Since the motor is continuously powered from the BATTery (to
enable the blades to park regardless of the position of the IGNition
switch), it can run at any time.

The remote possibility of what you're experiencing can be eliminated by
moving the long white wire from a BATT connection to an IGN source.

That's my best WAG. Smile

Ken H

Thanks Ken. It rained here before we got here, but I also spent the day yesterday washing the salt off of the coach. Maybe that did it. I think if I move power to a ignition source, it will still pulse, but when driving. I pulled the wires apart at the Weather connection on the motor and will let it dry out.....will see if that does it.

This did happen to me two years ago in the same spot in daughters back yard, and it happened at night in a heavy rain. We were watching TV and it just started pulsing all by it self. Don't remember what I did to fix it. HUH...two years ago...sometimes I can't remember past the end of my nose.


Larry Smile
78 Royale w/500 Caddy
Menomonie, WI.
Re: [GMCnet] Wipers pulsing? [message #271366 is a reply to message #271362] Sat, 07 February 2015 17:20 Go to previous messageGo to next message
Ken Henderson is currently offline  Ken Henderson   United States
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
Senior Member
Larry,

Thanks for that update -- now I'm more confident that my H20 diagnosis is
correct.

Ken

On Sat, Feb 7, 2015 at 1:08 PM, Larry wrote:

> Ken Henderson wrote on Sat, 07 February 2015 07:31
>> Larry,
>>
>> If you mentioned the prior incident, I've forgotten it, so I consider
> this
>> the first time I've heard of such.
>>
>> Has it been raining there, or have you recently been in rain?
>>
>> The intermittent sweep is controlled by a part of the PC board in the
>> motor. The sweep delay is set by an RC time constant where the
>> R(esistance) is the 500k Ohm sweep delay rheostat plus an in-line 680 Ohm
>> fixed resistor. If moisture gets into the Weather Pak connector on the
>> motor, or into the back of the motor covered by the black plastic plate,
> it
>> could reduce the R in the RC, perhaps far enough to trigger the sweep
>> circuit. Since the motor is continuously powered from the BATTery (to
>> enable the blades to park regardless of the position of the IGNition
>> switch), it can run at any time.
>>
>> The remote possibility of what you're experiencing can be eliminated by
>> moving the long white wire from a BATT connection to an IGN source.
>>
>> That's my best WAG. :)
>>
>> Ken H
> Thanks Ken. It rained here before we got here, but I also spent the day
> yesterday washing the salt off of the coach. Maybe that did it. I think if
> I move power to a ignition source, it will still pulse, but when driving.
> I pulled the wires apart at the Weather connection on the motor and will
> let it dry out.....will see if that does it.
>
> This did happen to me two years ago in the same spot in daughters back
> yard, and it happened at night in a heavy rain. We were watching TV and it
> just
> started pulsing all by it self. Don't remember what I did to fix it.
> HUH...two years ago...sometimes I can't remember past the end of my nose.
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
Re: [GMCnet] Wipers pulsing? [message #271418 is a reply to message #271366] Sun, 08 February 2015 14:22 Go to previous messageGo to next message
Larry is currently offline  Larry   United States
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
Senior Member
Ken Henderson wrote on Sat, 07 February 2015 17:20
Larry,

Thanks for that update -- now I'm more confident that my H20 diagnosis is
correct.

Ken


So, the weather connection was disconnected all day yesterday and didn't get a chance to hook up before bed last night. Well, the daughters home has a sprinkler system and guess what.....we forgot to turn it off, so last night at 3:00am, it came on as scheduled and soake the coach down before I got into the garage to shut the thing off. So...tomorrow, after it drys over night, I'll hook it up. One step forward, two steps back....One step forward, two steps back....One step forward, two steps back....and such is life. Very Happy


Larry Smile
78 Royale w/500 Caddy
Menomonie, WI.
Re: [GMCnet] Wipers pulsing? [message #271430 is a reply to message #271418] Sun, 08 February 2015 18:34 Go to previous message
USAussie is currently offline  USAussie   United States
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
Senior Member
Larry,

The adage of "you can't win for trying" comes to mind! ;-)

Regards,
Rob M.


-----Original Message-----
From: Larry

So, the weather connection was disconnected all day yesterday and didn't get a chance to hook up before bed last night. Well, the
daughters home has a sprinkler system and guess what.....we forgot to turn it off, so last night at 3:00am, it came on as scheduled
and soake the coach down before I got into the garage to shut the thing off. So...tomorrow, after it drys over night, I'll hook it
up. One step forward, two steps back....One step forward, two steps back....One step forward, two steps back....and such is life. :d

--
Larry

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Regards, Rob M. (USAussie) The Pedantic Mechanic Sydney, Australia '75 Avion - AUS - The Blue Streak TZE365V100428 '75 Avion - USA - Double Trouble TZE365V100426
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