Manager Forum

I got a 2001 Ford F250 Super Duty pk tk with a 5.4L gas engine and auto trans. Is 4wd. The issue is that intermittantly the horn will blow as you go down the road. Opening the drivers door will stop it until the door is closed, then it will blow again. It may go several days till it happens again. Also, the blower fan will run with the ignition key in the off position. This is also an intermittant problem. Earlier diagnosis led to the Body Control Module, so i replaced it with a new one from Ford. Same problem. What am I missing?

gem module

Check it for water damage, etc

The GEM. Is that the same thing as the BCM (Body Control Module)? It is located on the front side of the underdash fuse block? It has a new one.

Where would I look for water damage? When I replaced the BCM it was no sign of water in that area. I could take it back down and look closer. It is very easy to remove.

In examining a wiring diagram for the AC/Heater, there does not appear to be any connection between the BCM and the HVAC system. Am puzzled.

The gem is located on the back of the underdash fuse box. If you replaced that then there is a good chance the problem is in that fuse box.

windshileds leak water into it. Im sure the problem for both the horn and the blower are caused by the gem and/or the fuse panel

brianp87 wrote:windshileds leak water into it. Im sure the problem for both the horn and the blower are caused by the gem and/or the fuse panel

100%

You're suggesting what? Rubbed through wiring or the likes? Or should I just go to the boneyard and get a used fuse block and put that in?

Thanks for your time and ideas.

I have never had to more then the gem but have read were the fuse block may be issue. I would look for burnt spots due to poor contacts, loose conections, etc. Or maybe the new gem is defective.

Ya know, I suppose I'll have to drop that thing out again and examine it. The other issue this thing has is it has a trouble code relating to a power window circuit fault and this truck has manual window operaation on it. The old BCM had the code and after a minute or so, the new one had it as well. So it could be some rust? corrosion? You say water draining off the windshield? Did these trucks have a problem with that?

Lots of issues with water damage. ive done a few gems but nothing ever wiht the fuse panel but im in arizona. Good luck

sounds like the gem all the way. now have saying that i cant even begin to count all the gems i've seen where it has already been replaced and some idiot didn't attach the top screw securing it. eventually it pulls away and will cause problems. the gem will seal the back of the fuse box and usually deflects water. please don't hunt for a used one, install a new one.

Whatcha find?

Haven't had a chance to get the truck back in yet. But by going to Identifix as well as what this forum responses are, it appears that I will be focusing on the fuse box area. I already replaced the GEM and that did not solve the problem.

does this either have or had a remote starter?

No remote starter now or ever before. Farm truck on local dairy farm.