The other day I ran my 2001 SuperCrew through an automatic car wash, the next morning it started fine but I couldn't get it out of park, eventually found that my cab located #15, 5 amp fuse (stop lamp switch, speed control, brake shift interlock, GEM module, RABS module) was blown, I replaced it and went on my way, got to my location and turned it off, went to leave and same thing all over again. Replaced it again and started to do an item by item rule-out (messed with all the windows-nothing, turned on all the interior lights-nothing, hit the brakes and went from park to drive and back and forth-nothing, etc. etc.) drove it the rest of the day and it was fine. Got in it again this morning, worked fine and then I drove down my ex-wife's driveway (which is more like an off-road trail (but there were no wet areas), parked and shut if off and when I got back into it just 10 minutes later...same thing all over again.

The truck never got wet again since the car wash, so I don't believe it has anything to do with moisture as it has been pretty warm the last couple of days.

Anyone have any ideas???

Thanks!

- Justin

 

Have you checked the floor behind the CJB ( Central Junction Box / cab fuse panel ) ?

This would be at the edge of the carpeting where it is on the firewall.

A leaking windshield ( lower left hand corner ) can cause water to get on the back of the CJB, and corrode the pins to the GEM.
This is not uncommon, but not a chronic problem with 99-02 MY trucks.

The GEM can get corroded and cause all kinds of weird problems.

Here is a thread along this line, worth checking to see if there are signs of water ( aside from wet carpet, which could be dry by now could be rust on the firewall, and signs of water on the back of the CJB / GEM ).
https://www.f150online.com/forums/el...ease-help.html

 

SSCULLY...thanks for the info...I checked all of it out and there didn't seem to be any wet areas or signs of leakage...I had done some more checking online and a couple of people mentioned a wire problem with the trailer wiring harness and sure enough it looks like something had caught my harness and pulled three of the wires but only broke one (one of the lime green ones) so I repaired it and everything's good so far, however, I remain skeptical that it could be that easy...so we shall see. I will report back either way in case others have this problem.

 

Thanks for the update.

Not sure how that is, the Dark Green wire is the Right stop / Turn lamp on both the 4 pin and the 7 pin.

That is fused via BJB Fuse #19 10 A from the MFS.

CJB Fuse 15 ( 5A ) feeds the GEM, and CJB Fuse #6 ( not 100% that is correct, but that is the way the EVTM shows it ).

CJB Fuse #6 ( 5A ) is for the Shift interlock actuator and an instrument cluster feed.

Please do let us know what happens with this, if it does cure it.

 

Just like I figured, it didn't fix the problem, but I was able to isolate what chain of events causes the fuse to blow. I messed with everything connected to that circuit, even several things at a time trying to overload it...nothing, but It always happens when I am braking, turning left and have my turn signal on...weird, huh?

 

If you just brake hard at a stand still does it do it ?

Could be the Brake Pedal Position switch itself that is having issue if it does blow from a stand still.

Might want to take a look at the 4 wheel Anti lock brake system module with the ABS light being on, and if it does not blow unless moving.
This could be water in the 4WABS module connector.
This is in the front of the engine compartment, under the intake on the driver's side, next to the inner fender.
You are going to have to remove the air filter housing to get a good look at it.
The connector is a black with 3 pins.

The other could be the CHMSL on the back of cab, check that it does not have water in it, or a problem with corrosion in the bulb connector. I would imagine that this would be the case if you pressed on the brakes at any time.

Start with the 4WABS module connector, and work from there, checking for wire damage along the 4wABS harness.

 

Mines doing the same thing. I can not isolate the problem though because it is blowing the 5a fuse as soon as I put it in. There's gotta be a short somewhere though. What all does that fuse control? My wipers, dome light, 3rd brake light, and windows are all inop.

 

Disconnect the BOO switch and see if the short goes away. If it does, replace the switch.

 

BOO switch? Brake override? If so, is it the one located right by the brake pedal, the harness there?

 

Brake On Off switch or Brake Pedal Position Switch ( same device, old and new name by Ford terminology ).

It should be on the side of the brake pedal, with 3 wires to it.

 

OK, this thing has me stumped. The manual just says that it controls stop lamp switch, speed control, brake shift interlock, GEM module, RABS module. Why is everything else out? I just disconnected my dome lamp harness, the BOO harness, and tried a fuse and no luck. It popped a 10a and a 5a fuse immediately. Nothing is consistent except for that, so I have no leads to go off of since I cant get any power to anything...

 

I guess I can check the GEM later on today. I work graves, so I gotta crash but hopefully this is the culprit. I just wish there was an easier way to tell rather than having to tear it all apart

 

I took my truck in for the Speed Control Deactivation Switch recall, and then proceeded to try a fuse and everything works now. Apparently, the switch shorting out can cause a fuse to blow...Im guessing the little 5a one was the first to go...weird. And cruise works again

 

So the problem was you did not have the Secondary Safety switch for the Cruise Control replaced until this week ?

Just want to clarify, so I can add some keywords to the thread.

Thanks

 

Yea, I bought the truck recently from a friend at work, and after doingh research I saw that there was a recall on the Deactivation Switch, so I decided to take it in for that. Thats when I started looking up the recall a bit more and found out that if the switch indeed was puddled up with brake fluid, it can cause it to short out and fuses to blow, causing loss of wipers, dome light, windows, window wiper motor. Pretty much everything that was wrong with mine. So once the dealer was done with it, I tried another fuse, and it didnt pop. That was great too because it was raining banshees that day and it would have been miserable going home with no wipers!