I have had a slight battery drain on my Ford Ranger, enough to kill the battery after a few days of sitting. The battery is new.
This is the troubleshooting I have done so far:
Tested the battery unplugged at 12.67 volts. Tested the battery running at 13.7-14.3 volts.
Tested the amp draw resting at 0.27 amps. After 40 minutes this drops to 0.10 amps with the doors shut.
Tested the amp draw with the door opened but latch pressed in to simulate a closed door. Similarly at 0.27 amps until it drops again to 0.15 amps.
Removed fuse 26 with door open - dropped from ~3.8 amps to 0.15 amps (my guess is this controls the dome light)
Removed fuse 25 with door open - dropped from ~3.8 amps to 0.02 amps.
Repeated step 5 with the door simulated closed and after waiting for the drop for 40 minutes. Also dropped to 0.02 amps after removing 25. Before 25 was removed, 26 was removed with no effect (stayed at 0.15 amps)
I have concluded that fuse 26 is of no concern, since the simulated closed door at best gets 0.15 amps, and the result of it dropping with the door open is because of the dome light.
Fuse 25, according to this website controls the GEM and the speedometer.
My question is, what is the next best step to diagnosing the draw? My plan is to find all the components the GEM controls and attempt at unplugging them with the simulated door closed scenario, and seeing which kills the draw. Is this correct, or am I barking up the wrong tree?
The truck also has an aftermarket alarm system, which I have been wanting to uninstall for sometime. Is it possible this is routed through the GEM?