Hey guys. Several days ago, my wipers began operating in only the fastest speed. That lasted about a day and then they began functioning normally later in the day. On the way home today, the rear wiper suddenly turned on by itself (with it still in the off position) and I began hearing a whining high pitch noise from under the dash board. I pulled into the drive way and open the hood, it sounded louder and seemed to come from the A/C canister? But not sure. I turned the engine off and let it sit for a few minutes. Turned it back on the and high pitch noise was gone and the rear wipers were not operating.

Any ideas what's going on? Rig has never done this before.

 

Somehow, this is related to the climate controls. When I turn it on, the rear wiper kicks on again and high pitch noise starts up again.

 

There is no direct link between the front and rear washer circuits, other than they share a common washer pump which flips direction to push fluid either front or rear.

The front washer issue is most likely related to the Wiper Pulse Module, water ingress and corrosion affects the electronics in the module. If the problem persists, you can change either the module itself or the entire motor assembly, preferably the latter option.

Similarly there's no direct link between the rear wiper module and the climate control, how they can be linked is very odd. You could be unlucky and also have an issue with the rear wiper module.

Of course if there is a wiring issue, either a short or water ingress, then anything is possible.

Have there been any wiring changes recently (aftermarket equipment) or any leaks?

 

No upgrades or changes. I've noticed that the rear tail light is out is all. Aside from that, when I turn the climate control on, it creates the high pitch noise and the rear wipers turn on by themselves. Any ideas what could cause such strange electrical problems?

 

Any water leaks, wet/damp carpet on driver side? If so maybe water running down firewall and getting into the BCM?? Just not really sure - odd symptoms.