If I pull fuse^H^H^H^Hrelay #4 in the underhood power distribution box, will this disable the rear window defroster and leave my heated mirrors operational? And I can turn the remote start rear defrost option on again without risk to the rear window? And the rear defrost dash indicator will no longer work?

2014 XLT screw boost. Thanks.

 

Well, I'm the most recent victim of this.
Yesterday I warmed up my truck before heading out (38-40 degrees F) with the remote start and when I backed out of my drive way "BOOM" Sounded like a shotgun went off behind my head. I stopped in the middle of the road and jumped out with my pistol drawn, but nobody was around. I looked all over the truck and didn't see anything, so I headed to the gas station for more light and at first still didn't see anything.....then I saw it when I looked in the rearview mirror. The drivers side rear glass had shattered. I looked all over and did not see any impact to the window or around the window anywhere.


Go figure, 2014 Screw FX4 with 28k and stuff is falling apart on this truck. I'm trying to stay loyal as this is my 3rd Ford in 4 years. (2007Fusion had for 6 years, then 14 Mustang GT had for a year, then 14 F150 now)
1. Random Breaking Window
2. Transmission Chatters when downshifting on it's own (occasionally)
3. Transmission intermittent slips when in 6th gear and with light throttle at freeway speeds. (Occasionally)
4. Had to replace spark plugs at 26k due to misfires and fouling
5. Climate control will randomly go to lowest setting
6. Clunk in front suspension when fully cranked and backing up
7. Gas Mileage is getting worse, now around 14.5 MPG, was 16.5 MPG


With a sticker of over 50k you would think this truck would last and not have all of these issues. (I was going to pay this off next month, but now I'm not so sure) I was considering getting the New SD, but to be honest....I hate to say it, but I'm considering Chevy and Dodge at this point.


Have you guys seen all of these issues? What are your thoughts?

 

I tested this myself this evening. The answer seems to be "no."

I activated the rear defroster using the dash switch, then pulled relay #4. The mirrors would not heat up and the dash indicator went out.

I put the relay back in, and the dash indicator lit up. Ten minutes later the mirrors and the rear slider were noticeably warm to the touch in the 40-degree ambient temp.

Can anyone else confirm a similar experience?

 

On my 13 Lariat screw, I released the seat back on the passenger side and you can pull the corner of the insulation on back of cab out just a little and there is a black wire and a yellow wire with slide on connectors (Black is larger, yellow is smaller - you cannot mix them up) that connect to tabs on the rear window. I believe the pax side black wire is the power source, and the black wire on the driver side is the ground. I simply slid the connectors off the tab and insulated them. Window no longer heats, but mirrors DO. The indicator light on the switch no longer works, so as soon as mirrors clear I turn it off.
Now I wonder (and I do not have a wiring diagram readily available) if the smaller yellow wire is a control lead for the indicator light on the switch. Over the weekend I'm going to connect the smaller yellow wire back to the window and see if the indicator light works again.
BTW, you can replace the broken rear window many times & it may still break when heated. The glass is in a metal frame and expands faster than the metal & when there is no where to go -- BOOM - it shatters.
Looked at a 2015 ystdy, the rear window is NOT is a metal frame so not likely to break when heated.
There is a helpful YouTube video on how to release the seat backs on a 09-14 Screw cab.

 

According to the wiring diagram for my 2011, there is no fuse or relay for just the rear window defrost. You can unplug the connector to the rear window. It is behind the back seat pass side. Should be easy to spot. You will lose the indicator though. The indicator uses the power to the rear grid so as long as the grid is unplugged, the indicator will not work.

 

Just wondering out loud here, any of you that have had the misfortune of the exploding rear window, do you or did you also have the mysterious water leak that either comes from the third brake light or rear window itself??????????????

 

Interesting. Please let us know how this works out.

Thanks! I like the quality of this video. You don't have to pull the headrests as shown unless you're removing the seat.

 

Negative

 

Just a note the Super Cab rear back of the seat is removable but not like in that video. The latches are found at the bottom of the seatback.

 

Well, I'm sure we all feel much safer today.