2011 F-150 Heated mirror & rear window defrost problems
08-09-2017, 07:05 PM
#181
By the way mine is ambient temperature effected. What I mean is, at about 50 or so it stops working. As soon as it gets cold it starts working again. Not sure if this was the fix to stop the glass from overheater.
12-05-2017, 10:35 PM
#182
Biggest issue was that the 40 amp fuse was completely missing from my truck. No big deal, swapped it out with the inverter fuse and started troubleshooting. I did the little trick that Rickg1 did with the USB charger and that fixed my light on the dash. I went ahead and disconnected the rear defroster just to be safe and I think I have the mirrors working as they should, which is what I was really trying to accomplish today. Thanks a bunch for the tutorial!
Last edited by 46L281GT; 12-05-2017 at 10:39 PM.
09-24-2018, 09:25 AM
#184
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Hi defroster solutions
hello I solved the problem of the rear defroster here I leave a small diagram that I did half hahaha this is what happened to me and because the solution is easy and you only have to repair the area that is broken in the image, if you make a bridge exactly from where the cables of the multimeter are connected you can see that it starts to work perfectly as well as the light of the board as the heater, and well as I comment you just have to have connectivity again, either making an external connection or repairing the same as the window.
09-24-2018, 05:00 PM
#187
Paulino, You are right on the money! my congratulations. All should remember that a broken line will just render the defroster unusable but if this broken line touches the frame you are putting all the power on one window and it will shatter. I would suggest when fixing the the bad wire be removed at both ends, dont simply jump over it.
01-13-2019, 10:37 AM
#188
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I have been dealing with this issue for about a year. Yesterday I took it upon myself to do some trouble shooting and diagnostics.
Truck :2012 F-150 Lariat SuperCrew
Problem : Push rear defrost button on dash, and the light does not turn on. Mirrors do heat up. Defrost on rear window recieves 12v for a few moments, then nothing.
Diagnosis : Truck computer sees the input from the button and sends current to rear defrost through relay, waits to see if 12v signal is returned if is not, then it assumes the window is open.
Solution : My truck has a connector behind the rear passenger seat (behind the liner) that has 2 wires. The black wire is heavy and carries the 12v to the heating element of the rear defrost. The small yellow wire carries the signal from the mystery switch that is buried in the trim around the molding. This yellow wire also has a current limiting resister inline with the connector. My assumption is that this wire will be connected to 12v that is fed to the window through the mystery switch. I stripped a bit of the insulation from the yellow wire ABOVE the resistor (between the resistor and the window) and from the black wire before it connects to the window.Then I placed a
wire between the black heavy wire and the yellow wire effectively bypassing the mystery switch.
Conclusion : By bypassing the switch that is failing, the truck computer now sees the current is being sent to the rear defrost and completes the signal circuit. This allows the controls to light up the dash light, and also enables the timer for the defrost circuit.
Disclaimer : This worked on my truck, it MAY also work on yours, but do not hold me responsible if you decide to do this and your vehicle explodes, burst into flames, smokes, dies, or any other unforeseen issue.
Truck :2012 F-150 Lariat SuperCrew
Problem : Push rear defrost button on dash, and the light does not turn on. Mirrors do heat up. Defrost on rear window recieves 12v for a few moments, then nothing.
Diagnosis : Truck computer sees the input from the button and sends current to rear defrost through relay, waits to see if 12v signal is returned if is not, then it assumes the window is open.
Solution : My truck has a connector behind the rear passenger seat (behind the liner) that has 2 wires. The black wire is heavy and carries the 12v to the heating element of the rear defrost. The small yellow wire carries the signal from the mystery switch that is buried in the trim around the molding. This yellow wire also has a current limiting resister inline with the connector. My assumption is that this wire will be connected to 12v that is fed to the window through the mystery switch. I stripped a bit of the insulation from the yellow wire ABOVE the resistor (between the resistor and the window) and from the black wire before it connects to the window.Then I placed a
wire between the black heavy wire and the yellow wire effectively bypassing the mystery switch.
Conclusion : By bypassing the switch that is failing, the truck computer now sees the current is being sent to the rear defrost and completes the signal circuit. This allows the controls to light up the dash light, and also enables the timer for the defrost circuit.
Disclaimer : This worked on my truck, it MAY also work on yours, but do not hold me responsible if you decide to do this and your vehicle explodes, burst into flames, smokes, dies, or any other unforeseen issue.
This idea is intriguing to me. Do you actually cut-off the black going to the defroster or just splice in a wire to connect to the feedback loop. My thoughts are that it might be best to cut/disconnect to the rear defroster to eliminate any possibility of energizing circuit and therefore also hopefully eliminating risk of shattering back glass. Thoughts? Thanks!
01-13-2019, 01:38 PM
#189
rharlow,
Maybe some simplification would help. Remove the back seats and REPLACE not bypass the wire as Paulino described in his 9-24-2018 post. Read his post and my reply and you will have a simplified understanding of what is going on. I have gone into details on other threads and traced through the circuit with detailed exploitations. I am also more than willing to go into the exact process and mathematics as to why the window shatters.
The post is just meant to simplify. I would be very interested to know what happens when you replace only that wire. While you are doing so closely inspect the connections to see if there is anything that could come in contact with the metal frame. That is what shatters windows.
let me know if you have questions, I am interested in what you find.
Dave
Maybe some simplification would help. Remove the back seats and REPLACE not bypass the wire as Paulino described in his 9-24-2018 post. Read his post and my reply and you will have a simplified understanding of what is going on. I have gone into details on other threads and traced through the circuit with detailed exploitations. I am also more than willing to go into the exact process and mathematics as to why the window shatters.
The post is just meant to simplify. I would be very interested to know what happens when you replace only that wire. While you are doing so closely inspect the connections to see if there is anything that could come in contact with the metal frame. That is what shatters windows.
let me know if you have questions, I am interested in what you find.
Dave
02-13-2019, 10:16 PM
#190
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A way to get mirrors and light on dash to work
This idea is intriguing to me. Do you actually cut-off the black going to the defroster or just splice in a wire to connect to the feedback loop. My thoughts are that it might be best to cut/disconnect to the rear defroster to eliminate any possibility of energizing circuit and therefore also hopefully eliminating risk of shattering back glass. Thoughts? Thanks!