2001 Ford F-650 Electrical Problems - Diesel Forum

gillettebeanz · 03-07-2008, 02:38 PM

Hello, I am working on a 2001 Ford F-650 w/ a Cummins ISB in it. The problem was that intermittently it would continue to run with the key removed and it was also killing the batteries overnight. I was only able to get it to stay running once and was able to pull the Ignition Maxifuse in the underhood Junction Box to get it to shutoff. I checked for a draw at the batteries w/ the key off and found that it did indeed have one and the draw went away when I pulled either fuse 14 or 15 in the cab fuse panel i forget which one it was exactly 14 or 15. This fuse was the "GEM/Interior Light Relay" fuse 10a. With this fuse removed I have no more draw on the batteries, so I let it sit overnight w/ the fuse removed, and this morning the truck fired right up, but w/ the fuse removed I have no electric brake buzzing, no windshield wipers and a few dash lights do not come on. Put the fuse back in and everything works but it is drawing down the batteries. I am leaning toward the GEM module now, We are pretty sure the truck just got a new windshield in Dec. and this problem started shortly after so I suspect water has gotten in there. I was not sure if the GEM module could have anything to do with the truck staying running but it seems like it may. Has anyone had any similar experience, or any experience w/ these GEM modules? If it does need to be replaced does it need to be calibrated by ford or can i just throw the new one in? Sorry for the long post, but this problem is really bothering me. Thanks in advance for any help.

gillettebeanz · 03-08-2008, 01:26 PM

Hey guys, today i pulled the GEM module down and there are 2 harnesses going to it, I unplugged the 1st one and I still had a draw on my batteries, I unplugged the 2nd one and the draw went away. The one that made the draw go away had like 6 wires in it, while the other one had about 20 or so. To me this means that there is a short in the GEM causing it to draw power with everything off. I would think if the short was in the wires it would stay drawing on the batts when it was unplugged? Any one have any ideas? Thanks.

moparphreak70 · 04-28-2008, 09:10 PM

I just had the same problem on my 05 650 and I narowed it down to the fuse box under dash. Mine has corrision (the green monster) in the plug area and also on the inside of the box itself which dosent seem to come apart. Ford also had the part instock which suprized me so it must be a coomon problem, Now to find where the water came from.. I ll let you know what happens when I put the part in in the morning . To be continued....