Mamushka

Vehicle: 2012 F150 SuperCrew XLT, purchased new.

Problem: 2 to 3 years ago the driver’s side window would not roll down in the morning. Sometimes if I shut down the truck and opened the door (to kill accessories) and restarted the truck the window would work. As soon as it worked, it would work 100% of the time until the next day where it was a coil flip if it would work again. All other windows worked 100%. The issue started to get worse over time.

Read every post I could find about windows not working and best answer I could come up with was that the wire harness in the door might had a broken wire under the insulation due to the flexing. For some reason most 2012 F150’s have a connector in the door jam that rigidly holds the wires and when you open and close the doors the wires flex quite a bit. My truck did not have these connectors, so the wires were not subject to this extreme flexing that could break the wires. Regardless, I inspected the wires and would move the harness around while trying the window with no change. The window was totally dead until a restart.

Next best answer I could come up with was that the window switch got wet. During our frequent Florida rainstorms, opening and closing the door would allow some water to get on the switch, so I put in a new Ford master window switch as it was less than $40. No improvement.

I pulled off the door panel so I could wiggle the wires going to the motor from the switch. This would not “fix” the window if it was dead or “break” the window if it was working. Moving the wires in the door had no impact on the function.

Using FORScan I reset the BCM. No improvement.

I purchased a wire schematic for the truck. The front motor has 5 wires. Individually fused 12V constant, 12V switched (accessory), Ground and dedicated wires for the signal for up and down. The fuse was obviously good as window would usually work after restart. Ground was good as was a common ground for the system (still removed the ground, sanded to clean steel and reattached, no change.) The accessory 12V was good as the other windows worked. This essentially showed that the problem was somewhere in the door (3 wires related to the window that came into the door through the jam were all verified good) I checked voltage on the “up and down” wires but did not get readings that made sense (using a good Fluke meter). Looking at the schematic I figured out there is circuitry in both the window switch and the motor. This makes sense as the front windows have the auto up/down feature so it is sending some sort of signal vs. just a 12V “on or off”. Based on this I wanted to change the window motor. Found out the motor is part of the regulator so you have to change the whole thing. Great… Changed the window regulator with a new Ford one and… I works!... for a few months until it gets cool out. Then the same issue, mornings it won’t work.

Because of this I start trying different things and notice: Sometimes the window will start working on my morning commute. Usually after ~20 minutes into the drive (temperature issue as truck warms up?). Even more confusing, I left the window down a few inches overnight. When I tried to roll it down or up it rolled up. Did this a couple of times to verify. So it looks like the window, regardless of if I am pushing the switch up or down it is trying to roll up when it’s cold (60’s or lower). No clue how this can happen as there are separate wires for the up or down function.

Decide to change out the motor and regulator again with a Ford unit as I am beyond stumped. So far all good again, window is working 100%.

Needless to say, I’m not sure this fix will hold. I am beyond stumped at this point and it makes no sense how all of this could happen. Thoughts?

Pigcrew

Well good sir,
You definitely got my attention on that one. Using your signature, I pulled the wiring diagram just to make sure I could follow along.
Since you already replaced the motor/regulator assembly (twice) as well verifying the wiring in the door/hinge area and replacing the master window control switch the onl;y thing left is the BCM.

Since you mentionned that the problem is "going away" once the vehicle warms up, it lead me to think that there's something that moves and then make contact.
You probably heard the term cold solder joints before...if you didn't, look it up on Google.

Moving on, I believe your problem is residing in the BCM or at the connection of said BCM.

Before we jump to conclusions, have you followed the official pinpoint tests A and C from Ford ?
Have you checked if you have any BCM codes related to the windows?
Have you "intialized" the window motor after you replaced it?

I can provide you with the test procedures if need be.

Keep us updated

Mamushka

Very familiar with cold solder joints. I agree, the temp issue points to an intermittent connection. What is contrary to that is I have done a significant "wiggle test" with the wires with no change. Also once the window is working I cannot get it to stop working no matter what wirers/connections I move.
I did reset the BCM with no change, also since the BCM is in the passenger footwell I never moved the BCM wires/connector when I changed the regulator. As noted I fixed the problem with a new regulator (for now) so don't see how it's related to the BCM.
You mean reset the auto up and down? If so yes, it works as it should.
I do appreciate the feedback.