WIndows inop on a '12 F-150

Brad Clayton · February 26, 2013

This was a good one. Truck came in with a complaint of windows inop. The truck also had to be jump started to get to the shop.

I got it and was instructed to check for a draw on the system as the battery was just replaced. I checked the windows while the battery was refilling and noticed the rear switch led's were lit up with the key out. Next thing I noticed is the rear windows worked all the time. There was indeed a draw and I started pulling fuses, in the power window area. I was able to pinpoint the problem to a shorted circuit to power. Further diagnosis led to a faulty BCM.

I am not one to jump on a module replacement band wagon, so I dug into the module to have a little look see.

Posted Image

The "hot" bus bar in the BCM is bent just a smidge and laying on all the solder joints to the right.

batmantech · February 27, 2013

Nice find Brad,

I to hate the new module thing. Got 2010 F-150 with no power seats or power pedals. Pinpoints are 2 steps, check power and ground at DSM then replace module. I opened it up but can't see anything. Its getting a module.

Nice to see someone taking the time to properly lay out the fuses(in the top of the picture)

Brad Clayton · February 27, 2013

Nice to see someone taking the time to properly lay out the fuses(in the top of the picture)

I was wondering if anyone would catch that. :thumbup:

lmorris · February 27, 2013

"Cough" OCD "Cough".....

Brad Clayton · February 27, 2013

Posted Image

When the shop is dead, it's tough to fill the hours of the day. Posted Image

batmantech · February 28, 2013

FYI the new DSM fixed the concern.

And yes, I have seen stuff come in where someone has just put the fuses on a pile and put them anywhere.

Brad Clayton · February 28, 2013

Glad to hear it's fixed. Sometimes when I'm not a 100% sure, it's like a game show when I plug it in and turn the key on. It's nice to go home a winner!

YukonTyler · April 2, 2013

Had one like this the other day: 2008 F350 with no power locks. IDS shows inputs are working (switches and RKE fob). I can hear the non-serviceable relays clicking on and off inside the GEM. I get VBatt on either side of all actuators in the doors, and that for both lock and unlock. Looks like an open ground to me!

Load tested the ground for this circuit coming out of the GEM using an old sealed beam and the ground only dropped 100 mV. Looks like a bad ground circuit internal to the GEM.

Installed a new GEM and promptly let the smoke out. Lovely. Opened the old GEM to find the circuit board going to my power window ground pin fried. Opened my new GEM to find the same circuit fried immediately. All fuses remained good.

Dug into the door harnesses and found the l/rear harness to be in shambles. All wires were still intact but they were lacking about 1/4 inch of insulation all at the same point. The lock circuit had welded itself to the power window circuit. Lovely.

A harness, a second new GEM and a TPM sensor (to allow completion of GEM programming) was the fix. Successful day at the office.