Parasitic drain - GEM?

[rps944]

Hi all,
I'm in search of an opinion/advice. Vehicle in question is 2002 Explorer XLT w/tow package, early build.

After several days of jumpstarting, I have determined that the truck has a 250ma current drain, key off, etc. Factory specs say no more than 50ma is typical. Chasing down the culprit, it seems that the components behind fuse 2.20 (5A) are to blame. Pulling the fuse reduces the drain to 35ma. This fuse supplies the GEM (pin 1, constant hot), the driver's seat module, and the memory setting (truck has power seats but not position memory option). Disconnecting the power seat doesn't impact the drain. Can a GEM be "bad" and still function? I.e., everything works and nothing is flakey or intermittent. Or am I down the wrong rabbit hole altogether?

With F2.20 removed, everything seems to be working except the 4x4 high and low. (I also disconnected the 4x4 control module before removing F2.20 but that wasn't impacting the drain either). So, it seems that the GEM (or part of it) is drawing about 200ma in the key-off/removed position. Besides deactivating the 4x4, is there anything else I need to consider - like are the airbags still working? Also, before I started the current drain troubleshooting, I ran a full set of OBD-II (Ford-specific) and everything checked OK - no codes in memory or pending.

I know that GEM codes/self-test requires an NGS, or similar, scan tool. Can I replace the GEM myself and "reprogram" it on my own should I need/decide to? Or can I leave this as-is and, if needed, put the fuse back in when I need 4x4? (Which is rare.) Or should I just take it to Ford?

As always, advice/opinions/whatever is very welcome! Thanks!!
Bob

 

[rrgone]

I does sound like the GEM has failed, or possibly a chaffed wire somewhere downstream of f2.20. I don't think anyone in here has replaced a GEM because so few Gen 3s have 'em. You might try asking over in the Gen 2 forum, maybe someone over there knows about changing the GEM. Good luck, post back when you get it sorted out.

 

[rps944]

Thanks for the input

I appreciate your input. Before I get too crazy, I need to verify it is the GEM pulling the current. I didn't pull the GEM harness to measure the voltage/current at pin 1 yet - that'll wait for the weekend. And thanks for reminding me it could be as simple as a chafed wire. I tend to lose the forest through the trees at time.

I also need to verify that the GEM has some control over the 4x4 which I think is not kicking in (4x4 L/H indicators light but don't notice a differrence). I need to put the fuse back in and recheck. If it's still not going into 4x4 I need to see if that's related to the current drain (possibly pulling through the GEM?) or I have a separate problem.

I also want to see if the truck's battery/charging system cooperates the next few days. My wife said the truck cranked over this morning but a little slow at first. Since I killed the battery yesterday while testing and had to jump it, and only did a few local miles, I'm not certain the battery got much of a charge. Plus, the temp is dropping into the 30s overnight now - not really cold enough to kill a battery but enough to make a difference on a weak one.

I'll keep the forum posted as to my progress/frustration