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Just so everyone is aware if you are experiencing intermittent issues with your rear defrost LED ensure that if you have warranty this is noted and fixed.
While my truck was under warranty I had occasional issues but never really thought to bring it up. Summer rolls bye and my warranty and this fall rear defrost has given up the ghost.
I was quoted 1600 dollars plus tax for rear window replacement.
If I had any idea this intermittent little problem was a 1600 dollar problem I would have dealt with it immediately under warranty.
Who woulda thunk.
On my truck I have checked the fuses. All good. But in position #4 it looks like there should be a relay for Heated Mirrors and Backlit, whatever that is. I'm going to try dropping a relay in there and see what happens. The led light on the dash lights up when I push it, but mirrors do not defrost. No defrost in the back window on this ride, so isn't the widow contact. 2009 Lariat.
It worked. Picked up a relay and installed it yesterday. Mirrors were frosted over this morning. Punched the defrost button and like magic they defrosted.
Anybody know how the 12vdc get to the driver side??
I have 12v on the passenger side and the switch is working like it should cutting the power on and off, just not getting the dash light. And the ground is good.
When I jump a wire from the large power wire to either of the window contact the light on the dash comes on like its working fine.
So I know the problem is just getting power from the passenger window to the contact for the sliding window, but there is no wire or anything running to that side? guessing it is in the frame of the window?
Here is a diagram. Looks like power goes thru connector C3368 with power from the defrost relay on the brown-yellow wire and the white-orange wire carrying the defrost signal to the HVAC module. Maybe only a few volts. The ground shows to be at the opposite end of the window from the connector. That 3368 connector is behind the passenger side rear seat.
I have been reading this thread most of the day now and please allow me to approach this from a different angle.
My Dad borrowed my truck and didn't know I had power sliding windows,he thought that black thing was the latch and wasn't taking no for an answer, so it ended up in my cup holder.
I am and electrical engineer by education, repair and detailed diagnostics is my trade, I have been self employed for 23 years. No matter what your specialty is you have to be grounded (no pun intended?) in the basics.
I have doctored up the drawing to show the primary path of the current flow and the secondary path of the logic signal. At first glance it looks like wire 1 and 2 are the main lines but only #2 provides current flow through the 3 glass sections and then grounds to the frame. It is really kind of clever that Ford took advantage of the 3 sections and used it as a voltage divider to create the logic signal of 4 to 5 volts.
The real issue here is, and I believe only is, the point were the wipers make contact with the stationary window. There is a lot of current and little voltage flowing through these two connectors so it doesn't take much to open the circuit. The wipers get weak and just dont make contact. As a result no "OK" signal is sent to the module and it stops working.
Being torn off I had the advantage of looking at it closely and to be able to bend the wipers for a better fit, still there isn't much room as you dont want the wipers bent in so far as they contact the glass, unless you dont mind scratches. There is a way to create more tension on the wipers but it has to be taken off the window. The other side is soldered directly to the contacts mounted in the glass. If you know how to solder it isn't too hard but to a novice too little or too much heat can be risky.
If there is interest I could do a YouTube video on how to solder to the window. I kind of expect mine to fail in a short time, that is when i will stiffen the wipers.
The quick test for anyone out there is to simply push on the black latch or move it slightly. One could even place two small pieces of foil to see if it starts to work. Based on what I read and what the diagram shows I would not be surprised if there are a few variations in the design, if so please let me know and i will think it over.
I know some folks gripe about the design and who wouldn't if you had to pay $1000 to fix it, but overall this is a sturdy, dependable and solid truck. I am a skeptical guy so I figure the dealers see this as a way to make big bucks.
I have been reading this thread most of the day now and please allow me to approach this from a different angle.
My Dad borrowed my truck and didn't know I had power sliding windows,he thought that black thing was the latch and wasn't taking no for an answer, so it ended up in my cup holder.
I am and electrical engineer by education, repair and detailed diagnostics is my trade, I have been self employed for 23 years. No matter what your specialty is you have to be grounded (no pun intended?) in the basics.
I have doctored up the drawing to show the primary path of the current flow and the secondary path of the logic signal. At first glance it looks like wire 1 and 2 are the main lines but only #2 provides current flow through the 3 glass sections and then grounds to the frame. It is really kind of clever that Ford took advantage of the 3 sections and used it as a voltage divider to create the logic signal of 4 to 5 volts.
The real issue here is, and I believe only is, the point were the wipers make contact with the stationary window. There is a lot of current and little voltage flowing through these two connectors so it doesn't take much to open the circuit. The wipers get weak and just dont make contact. As a result no "OK" signal is sent to the module and it stops working.
Being torn off I had the advantage of looking at it closely and to be able to bend the wipers for a better fit, still there isn't much room as you dont want the wipers bent in so far as they contact the glass, unless you dont mind scratches. There is a way to create more tension on the wipers but it has to be taken off the window. The other side is soldered directly to the contacts mounted in the glass. If you know how to solder it isn't too hard but to a novice too little or too much heat can be risky.
If there is interest I could do a YouTube video on how to solder to the window. I kind of expect mine to fail in a short time, that is when i will stiffen the wipers.
The quick test for anyone out there is to simply push on the black latch or move it slightly. One could even place two small pieces of foil to see if it starts to work. Based on what I read and what the diagram shows I would not be surprised if there are a few variations in the design, if so please let me know and i will think it over.
I know some folks gripe about the design and who wouldn't if you had to pay $1000 to fix it, but overall this is a sturdy, dependable and solid truck. I am a skeptical guy so I figure the dealers see this as a way to make big bucks.
Dave
Hello Dave, thanks for posting the info on the rear defrost problem. My first question is what year F150 do you have. Next, is it possible to get the plastic cover off of the contacts without breaking the solder joint on the glass, this
would be an issue if I wanted to increase the tension on the wipers and not
be able replace the wiper cover.
I am pretty sure that the plastic housing was installed after the metal wipers. It mounts from the top and pushes down, The picture I doctored shows the piece with the top facing down. Notice the two tabs with black silicone glue on them, at assembly they must of smeared it with silicone, placed it a little high and slip it down into position. So I guess it might be possible to tap it up and break the glue bond. Still there is an internal tab so I wouldn't try too hard.
I am thinking of two ways to go at it, one is to illustrate where to cut away at the plastic with a Dremel bit to expose the contacts, the other relates to Smoke Rose, I should be able to design a small plate that pushed into the crack and "thickens" the tension. If it works like my minds eye imagines it should be able to be slid into place and adhered with a quality clear tape. It isn't my preferred method but it would require no soldering skills.
I am in the process of taking pictures of my 2011 soldered in place without the black cover, I just need some time as the Packers play tomorrow and I am making Tenderloin for Xmas.
11-16-2016, 12:42 PM
Don't ignore
