Can't seem to find anything with the search function, so I'll ask here and hopefully someone knows the problem

In my 2007 Caravan after a light rain, when turning on the rear defroster there is obviously water somewhere. Once I push the button, the radio, heater fan, rear wiper, defrost (anything in the center console where the radio is located) turns off - on - off - on - off - on ect.

If I leave the defrost off and run the air conditioning for about 10 minutes, the problem goes away. Obviously I have water leakage somewhere, but any idea where?

 

Welcome to DF
By any chance are you smelling coolant or loosing coolant from the radiator?

Welcome to DF
By any chance are you smelling coolant or loosing coolant from the radiator?

 

No coolant loss.

 

Ck the drain tube and see if the water from the A/C is draining.

 

Actually, this problem happens without the A/C, only after it rains. Since it is a lot cooler here in Ontario the A/C is only on for about two weeks per year in July. I only turn the A/C on (with the temperature set to maximum heat) to dry out the water that is somewhere inside my vehicle (I'm guessing behind the radio) but I don't know how it is getting inside

New windshield was put in and the problem didn't go away, so I'd assume it isn't likely the seal around the windsheild. I'm at a complete loss.

 

It also could be a corroded ground or wire in the engine compartment that looses continuity when it gets wet. It doesn't have to be a water leak. For it to get wet by the center stack would almost be impossible. And a water leak by the bulkhead connector, you should be able to look under the footwell and see it wet.

 

It sounds like a chassis ground to me. The rear defogger is a very high draw accessory. It wouldn't surprise me if it was the trigger for the failure of a poor ground. An easy way to test is run a jumper cable from the negative post to something solid on the chassis. Or better yet just add a new one. I always add a new solid chassis ground strap when I buy a new vehicle.

 

Thanks to both the previous posters, I'll look into the chassis ground