Rear wiper wont work when cold?

[alamantia]

2005 tahoe. When its warm out I click the switch and the wiper works. When its cold out I click the switch and it doesnt work. I drive it into my garage and let it sit in a 60 degree atmosphere for 20min and when I click the switch it works, back it out of the grage to where its 20 degrees and click the switch and it doesnt work. I took the tail gate panels off and ttried it and same thing. I could understand if water was freezing but its totaly dry. I wonder if there is some stupid mercury switch which prevents it from working in the cold, if so I never heard of that before.

[Tru2Chevy]

I would be curious to see what happens if you turn it on in the garage and then back out into the cold and see if it stops working or keeps going. I've never heard of any type of temp switch that would prevent the wiper from working.

- Justin

[sweetbmxrider]

The rear liftgate ajar switch is tied into the circuit and prevents wiper operation if the switch is open. Definitely a strange problem. Does the washer still work even though the wiper doesn't? Did you try checking for power at the motor when it doesn't work? Try banging on it like a stuck starter?

[JL8Jeff]

Maybe when it's cold something is contracting(weatherstripping?) and the rear lift ajar is being detected which overrides the wiper from working. But I would you'd be seeing the rear lift indicator light going on. When it's not working, maybe have someone push in on the rear tailgate and try again. If it works, that might indicate it thinks it's open.

[alamantia]

The washer works and I can hear the solenoid clicking when I hit the switch. I removed the panels and unpluged it and cleaned the contacts (knowing full well that has never resolved any electrical issue in my life, but I always try it anyway hoping for that one day it actualy yeilds some miricale result) put everything back together and the same. Door closed, no operation when cold, drive it into garage and after a few min it works. I did a google search and I see someone has the identical issue but with a jeep, no resolution is shown in the forum though.

http://www.jeepforum.com/forum/f28/rear-windshield-wiper-wont-work-cold-673859/

I see a GM motor is around $200 where a dorman is only $100. Id hate to replace a non returnable motor for nothing.

[V]

can you try having the truck outside, all cold, get it to the point that its not working, then use a hairdryer or heat gun to heat up the wiper motor only, and see if itll start working. if not, try heating up different areas to see when it will work.

[JL8Jeff]

Is it a solenoid clicking or a relay clicking? Either one could be going bad but a solenoid might have some grease that gets cold and won't function properly.

[alamantia]

can you try having the truck outside, all cold, get it to the point that its not working, then use a hairdryer or heat gun to heat up the wiper motor only, and see if itll start working. if not, try heating up different areas to see when it will work.
Good idea

Is it a solenoid clicking or a relay clicking? Either one could be going bad but a solenoid might have some grease that gets cold and won't function properly.
I figured that the relay was under the dash and the solenoid was on the motor in the tailgate. I could be wrong about the relay location but the noise is coming from the tailgate

The rear liftgate ajar switch is tied into the circuit and prevents wiper operation if the switch is open. Definitely a strange problem. Does the washer still work even though the wiper doesn't? Did you try checking for power at the motor when it doesn't work? Try banging on it like a stuck starter?
I thought of that but I figured this would be the same switch the dome light is on and the domelight isnt coing on when the tailgate is closed, it only comes on when the tailgate is open. I could be wrong though. I could search a schematic on all-data tonight.

As a matter of fact, where is the domelight switch for the tailgate? Its not a plunger style like a door jamb that I could see. Is it a mercury switch within the gate or a limit switch on the latch? I have no idea. Are there seperate switches for the domelight and the liftgate ajar light?

Regardless, although I would like to figure this out now, it is a pretty low priority. But if anyone has any additional ideas, I am open to your suggestions. Thankd for all the replies so far.

[alamantia]

it was a bad ground

[sweetbmxrider]

Damn, always check your grounds! I guess it was losing connection when the metal contracted?