Home » Public Forums » GMCnet » Uncommanded electric windshield wiper operation
| Uncommanded electric windshield wiper operation [message #215469] |
Tue, 23 July 2013 15:29  |
rjw
Messages: 697
Registered: September 2005
Karma: 4
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During a recent trip to the Upper Peninsula of Michigan, out of the blue, our electric windshield wipers decided to turn themselves on. No amount of fiddling with the delay or on/off switches could stop the wiping. I had to turn off the highway and pull the fuse to get them to stop.
A few days later I replaced the fuse in advance of entering an area of thunderstorms. The wipers worked normally and I could turn them on and off no problem.
Previously, I had replaced the wiper motor because the original junkyard motor quit during a rain storm. I replaced that with a new rebuilt motor from Advance Auto Parts with a lifetime warranty.
Doesn't seem like any of the components supplied by Ken H. could be at fault. Certainly couldn't be caused by the way the expert GMC motorhome technician (me) installed the system.
Could I have another bad wiper motor? Can they turn themselves on?
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.
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| Re: Uncommanded electric windshield wiper operation [message #215497 is a reply to message #215469] |
Tue, 23 July 2013 20:21  |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Senior Member |
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Jim Bounds described this and the fix on his site somewhere. It's the variable speed switch. If I recall correctly, it has to do with wear in the switch that lets the contacts close when you hit bumps or similar. He described a simple fix that I think involves filing the bottom notch a bit deeper.
Sorry I don't know the whole process but it's on the coop site somewhere.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] Uncommanded electric windshield wiper operation [message #215502 is a reply to message #215497] |
Tue, 23 July 2013 21:17 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Kerry,
Huh? That don't compute for me. I think maybe you're confusing a fix for
the OEM wiper lever with Richard's electric wiper problem. It's very
doubtful that Jim, or anyone else, has opened and repaired the well-sealed
CH PtW/TtW switch I deliver.
Richard,
This is the first time I've heard of that problem, but I'll bet that
water's getting into the "sealed" electronics compartment of the motor.
I'd remove the motor and open the cover on the back side. Be sure its
perfectly dry inside, then seal the cover with silicone, Goop, plumber's
putty, chewing gum, or grease. Even a drop of water in the right place can
cause the problem.
The way the delay circuit works is that a monostable multivibrator (pulse
generator) periodically activates the Park function of the motor -- that
circuit is powered regardless of the wiper switch position, and possibly
even the ignition switch, dependent on where your circuit breaker is
connected. The frequency of the multivibrator is set by the Resistance in
an RC delay circuit. If a drop of water shorts the R, the delay approaches
0 and the motor "parks" continuously.
JWIT,
Ken H.
On Jul 23, 2013 6:21 PM, "Kerry Pinkerton" <Pinkertonk@mchsi.com> wrote:
>
>
> Jim Bounds described this and the fix on his site somewhere. It's the
> variable speed switch. If I recall correctly, it has to do with wear in
> the switch that lets the contacts close when you hit bumps or similar. He
> described a simple fix that I think involves filing the bottom notch a bit
> deeper.
>
> Sorry I don't know the whole process but it's on the coop site somewhere.
> --
> Kerry Pinkerton
>
> North Alabama, near Huntsville,
>
> 77 Eleganza II, "The Lady", 403CI, also a 76 Eleganza being re-bodied as
> an Art Deco car hauler
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Uncommanded electric windshield wiper operation [message #215504 is a reply to message #215502] |
Tue, 23 July 2013 21:37 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Senior Member |
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| Ken Henderson wrote on Tue, 23 July 2013 21:17 |
Kerry,
Huh? That don't compute for me. I think maybe you're confusing a fix for
the OEM wiper lever with Richard's electric wiper problem. It's very
doubtful that Jim, or anyone else, has opened and repaired the well-sealed
CH PtW/TtW switch I deliver....
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Duh! I should read more carefully or, better yet, not write after a 750 mile drive... LOL
Sorry....wrong problem...
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] Uncommanded electric windshield wiper operation [message #215537 is a reply to message #215502] |
Wed, 24 July 2013 09:31 |
rjw
Messages: 697
Registered: September 2005
Karma: 4
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Senior Member |
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| Ken Henderson wrote on Tue, 23 July 2013 22:17 |
This is the first time I've heard of that problem, but I'll bet that
water's getting into the "sealed" electronics compartment of the motor.
I'd remove the motor and open the cover on the back side. Be sure its
perfectly dry inside, then seal the cover with silicone, Goop, plumber's
putty, chewing gum, or grease. Even a drop of water in the right place can
cause the problem.
The way the delay circuit works is that a monostable multivibrator (pulse
generator) periodically activates the Park function of the motor -- that
circuit is powered regardless of the wiper switch position, and possibly
even the ignition switch, dependent on where your circuit breaker is
connected. The frequency of the multivibrator is set by the Resistance in
an RC delay circuit. If a drop of water shorts the R, the delay approaches
0 and the motor "parks" continuously.
JWIT,
Ken H.
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Ken,
So it sounds like I have a problem with the motor. I didn't really think the switches, wiring or installation could be the problem. Then again I didn't know if the motor could run independent of the controls. You confirmed that it is possible. To save time (I have a trip to get the coach ready for next week)I think I will just get another motor since I supposedly have a life time warranty. I'll let you know the results. Thanks for the feedback
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.
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| Re: [GMCnet] Uncommanded electric windshield wiper operation [message #218436 is a reply to message #215502] |
Thu, 15 August 2013 09:17 |
rjw
Messages: 697
Registered: September 2005
Karma: 4
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Senior Member |
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| Ken Henderson wrote on Tue, 23 July 2013 22:17 |
If a drop of water shorts the R, the delay approaches 0 and the motor "parks" continuously.
JWIT,
Ken H.
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Ken,
After another trip where I didn't have working wipers (they were disconnected by pulling the fuse) I decided to try to fix the problem by installing a new motor. Before I pulled the 3 month old rebuilt motor, I made sure it was actually running ("parking" continuously) by putting the fuse back in and and turning on the ignition with the wiper switch "off". Yes, it ran when it was not supposed to be running.
I pulled the motor and took it back for a free replacement at Advanced Auto parts (lifetime warranty). I got home and installed the replacement motor. With fuse in, ignition on and switch "off", lo and behold, the new one doesn't run except when it is supposed to.
So Ken, your theory was right. It's a relief to know that the problem wasn't caused by something I did wrong when I installed your electric wiper system.
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.
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