1999 Ford F350 1999 F450 250ma draw...could be GEM? Fues 1

autobahn_parts · Posted at Sun Nov 01, 2009 7:04 pm

Electrical problem
1999 Ford F350 V8 Two Wheel Drive Automatic 185,00 miles

I am having a problem with my truck killing the batteries. It has a 250ma draw when everything is off. When I unplug fuse 15 under the dash, it stops the draw. It's a little 5amp fuse. I printed out the wire diagrams on the truck and traced it back to the brake pedal or the "GEM" on top of the fuse box. It was not the brake pedal sensor, but when I unplugged the GEM it when down to 30ma. Have you ever seen the GEM's go bad and draw power like that? I noticed the little relay #1 in that under dash fuse box is also pulling a little power, but not the whole 250ma. The GEM Part number is f81b 14b205 gb with a big G after it. 03/25/99 production on it.

Jacobandnickolas · Posted at Wed Nov 04, 2009 7:17 pm

Some of the 99's had issues with water leaking from the driver's side windshield and causing problems with the GEM, fusebox and from time to time the PCM. Based on your description, I have a feeling this is the problem and the GEM needs replaced. Keep in mind, the window motors, door locks and AC fan... are controlled by the GEM. A short to any of them could cause a draw too.

Do you loose the draw when individual fuses are pulled?

autobahn_parts · Posted at Wed Nov 04, 2009 7:34 pm

When I pull the #15 fuse that kills the draw. It's a 5 amp fuse. I don't think any other fuses did anything. Should I go back and check again? I know when I pulled the #1 relay, it cut down on some of the power consumption... down to about 150ma or so.

Jacobandnickolas · Posted at Wed Nov 04, 2009 8:28 pm

According to the owner's manual, what does #15 power?

autobahn_parts · Posted at Wed Nov 04, 2009 10:11 pm

GEM Generic Electronic Module
PCM Powertrain Control Module
ABS Anti Lock Brake system Module
Brake Shift Interlock
Speed Control

For the last two hours I was under the dash unplugging connectors and replugging while my buddy looked a the multimeter. Nothing. The only want to get it back down to .02 amp is to pull the top plug from the GEM.

Jacobandnickolas · Posted at Thu Nov 05, 2009 6:16 am

I see that you removed it. Have you tried a different one?

autobahn_parts · Posted at Thu Nov 05, 2009 6:46 am

I have not had any luck finding one. My understanding is that the last two letters have to be exact. That is the hard part. And they are $600 new!!!

Jacobandnickolas · Posted at Thu Nov 05, 2009 8:31 am

Is there any evidence of a water leak?

autobahn_parts · Posted at Thu Nov 05, 2009 5:40 pm

Have not seen any signs of water. The board inside looks good. I need to find a used one, but that has proven to be not that easy.

Jacobandnickolas · Posted at Thu Nov 05, 2009 6:45 pm

Have you tried on line salvage yards where they search the country? I have a good friend that owns a salvage yard. I'll see him Saturday AM (I need parts for my truck). THey have about 5 acres of cash for clunker vehicles (nicer than the one I'm driving). If you want, I'll check for you.

Let me know.