Electrical Issue - BCM?

[Captain_Mike]

Hey everyone. I've found countless answers here and a lot of great advice. I'm hoping you can come through once again.

Problem is - It's been going on for about a month now progressively getting worse. Once I start the truck, 02 Sport trac 2x4, and press the brake pedal or roll down my windows, one of the relays up under the dash starts buzzing, my interior lights, along with my compass, and radio lights flicker. At first, a month ago, if I opened and shut the door hard it would stop and I wouldn't happen for a week but as I said it's gotten much worse.

At first I though I'd swap out the relays just to see-no difference.
Secondly I've pulled the drivers door skin off and removed all plugs and checked all wiring - nothing.
At this point I've started considering the Body Control Module (BCM). It seems that this is the only thing that has some connection to all of the symptoms I'm having.

So any input is GREATLY appreciated. Also if anyone knows where this precious little part is, please pass on the secret location. It's not under the center console.

Thanks again!!!

 

[bdmaash]

sounds like power delivery issues
when you press the brakes, it uses power to light up those bulbs in the rear
when you actuate your windows, the motors use power to move the windows up and down.

look for bad ground and power connections - the ones that supply those circuits would be a good place to start.
But then again, switching out random parts might be a much smarter approach.

 

[Captain_Mike]

Hey all. I appreciate the info. Since last posting I've found out that Ford calls the BCM the Smart Junction Box, Multi function module, or the GEM. All the same part number. It was located to the left side behind the radio. I found a used one for $45, compared to $380 new, and installed it. The symptoms pretty much went away, about 90%, but are still slightly there, indicating that that's not the problem but being the problem has gone on for some time it might have had an affect on this module. I've checked the door wires and all appear to be intact. Now here comes the strange thing. Although I've used a scanner before with no luck, to take a shot in the dark and see if it throws up codes. I decided to try it again while I hold the window down and make the symptoms occur and everything worked perfectly as long as the scanner is plugged in. No idea why. I unplugged the scanner and the symptoms return. So until I figure this out, the scanner is plugged in and zip tied up under the dash. Is there any way it could be the voltage regulator? The only time the symptoms occur is when there's "excessive" draw. For example when the windows already down and I push the window down button etc.. I know it could definitely be a bad connection but don't have the patience to go down that road quite yet.

I appreciate the help.

 

[ncranchero]

Next thing I would check would be all the grounds you can find. There are some on the inner structure near the battery, behind the right kick panel, center of the cowl. A loose or bad ground will do really strange things and run you crazy.

OK, there is a ground in the main harness that is common to the items you list as whacky. It is behind the left kick panel........check it. You could be drawing a ground through the DLC while the scan tool is plugged in.

 

[chad551]

I had this issue in my ST, when my drivers side window switch module was broken. I broke one of the window switches and it was causing a short.

 

[Captain_Mike]

Next thing I would check would be all the grounds you can find. There are some on the inner structure near the battery, behind the right kick panel, center of the cowl. A loose or bad ground will do really strange things and run you crazy.

OK, there is a ground in the main harness that is common to the items you list as whacky. It is behind the left kick panel........check it. You could be drawing a ground through the DLC while the scan tool is plugged in.

You are the MAN! It turned out to be the ground behind the driver side kick panel, G300. Unreal!! One simple ground can cause that many headaches. Can't thank you enough. Hopefully this will prevent others from having the same issues.

 

[ncranchero]

LOL !! I feel like the blind squirrel that just found a nut!

 

[Captain_Mike]

I'll second that! Thanks again.