Since I live in the Great White North I use my rear window defroster & heated mirrors when it snows. I noticed sometimes that it did not work and was wondering if there was an issue with them. I had checked the fuses etc and could not see where they would stop working at times. Then I found the reason for it. I have a power rear window and I like to open it a slight crack to help in getting the airflow through the truck which heats it up faster. When the rear window is opened ... it turns off the defroster function. I found this interesting and wanted to tell others about this as they may run across the same situation.

 

It's because the rear window completes the circuit

 

^ Yep... the contacts only make connection when the sliding part is closed all the way.

 

I do not have the rear window defroster but i do have them in the side mirror. 10-20% of the time ihave to cycle the button on and off before it works.

 

Owner's manual, 2d edition, page 71:


REAR WINDOW DEFROSTER (IF EQUIPPED) R
The rear defroster control is located on the climate control panel and
works to defrost your rear window from fog and thin ice. If equipped, it
also operates the heated mirror to remove snow and thin ice from the
side mirrors.
Ensure that the ignition on. Press to turn the defroster on/off. The
indicator light will illuminate when activated. For vehicles with a sliding
rear window– the defroster will be disabled when the window is opened.

 

This past weekend, I thought my defrosters were broken or that there was something wrong with the light in the climate control button or it had a bad connection within the dash. I was able to get the light to come on when I swerved back and forth so I then knew it was something making a poor connection somewhere. I finally traced it down to the rear sliding window not making the contact reliably when closed. I pushed the button, had no light, climbed into the back seat and pushed on the sliding window glass...light on dash lit up...removed my hand from the glass...light went out. I am now wondering if there is a way to adjust this alignment myself without having some greasy tech climbing all around my new interior while trying to figure this whole thing out. Anyone else have this issue?

 

No, it's because the wires stretched!

 

So...nobody else is having issues with the defroster contacts on the power sliding rear window causing the whole side mirror/rear defrost circuit to not function besides me?

 

My issue is rear window defogger is faulty, they want $800 to replace it and now my side defoggers don't work because they are all connected. Called Ford and they would do it for $475 - that is not customer service! I paid $2600 for the "Premium" extended warranty from Ford and they won't cover the window.

 

Yeah, I had that problem, although I never got into the back seat to try what you did.

When I took the truck in for the rear defrost not working, the tech replaced the command module in the dash, the part with all the HVAC buttons on it.

When that didn't work, he ordered a whole new back glass assembly, per Ford's SOP.

They did a good job replacing it, and minus a little glue left over, I'm happy. Apparently the window position switch goes bad, which is why you're getting intermittent connectivity (I think). Mine flashed a few times, but eventually stopped working altogether.

The rear defrost actually still worked, but the light in the dash is to turn the LED on in the button.

-John

 

I have a 2013 xlt with sliding rear window. My rear window defrost has never worked. My window is closed, but I'm going to try moving the window to see if it helps. One thing I will tell, I had a service Manager tell me the reason it wasn't working was because the window had to be completely covered with ice, or snow. I'm pretty sure he was full of s---. I also read on another site that quite a few people had trouble with the rear windows breaking when using the defrost cycle. Supposedly a Ford problem??

 

The light on the dash of my 09 lights up. Fuses are good. The mirrors and rear window do not defrost. Dunno.

 

Has anyone tried running a jumper wire to bypass the faulty back window so at least the mirrors will defrost? I found out how to drop the back seat, so I might be able to find the wires.

 

WTF! Time to lawyer up!

 

My defrost was working some of the time, now it quit working all together...