I'd like to run my troubleshooting thus far by somebody (RonD maybe?) to see if I'm on the right track. I have a 99' B-2500 4x2, M/T.

Symptoms:
Battery drains flat after sitting for 2+ days. Drains from 12.4V to 11.7V overnight, down to 11.3V if I leave it for 2 nights.

Steps so far:
1) Checked that battery was not internally shorted by charging it up to 12.7V, disconnecting positive cable and leaving overnight. Stabilized to 12.4V, no change in voltage after 8 hours.
2) Checked charging system at auto parts store, alternator is strong at idle and under load.
3) Checked for parasitic drain, 0.22A with key out, all lights off, doors closed. Isolated drain to fuses 25/26, battery saver relay and GEM.
4) Pulled the battery saver relay and bench checked it with a 12V drill battery, relay checks good.
NOTE: Any future B-2500 owners, save yourself some trouble. The battery saver relay in a 99' B-2500 4x2 is located behind the glovebox and is an isolated, single relay. It is NOT in an aux relay box under the dash to the right of the steering column. There is no aux relay box, don't waste your time pulling dash panels as I did searching in vain.
5) Checked power at fuse 26, power leading to battery saver relay and continuity between GEM and relay. All check good.
6) Running out of ideas, I reinstalled the relay and left the door cracked open so the dome light was left on. Came back after an hour and the light was still on. Given that the relay and the wiring between the relay and GEM are good, I suspect the timer in the GEM is faulty and is never de-energizing the battery saver relay.

My question: Is this a common failure mode for this type of fault? Is the GEM timer failing more common than the relay failing? I suspect the previous owner knew about this issue, there was a disconnect switch installed inline between the negative battery terminal and the negative cable. I originally thought this was for ease of maintenance, but more likely he had the same battery drain issue and couldn't be bothered to troubleshoot it.

Sorry for the long-winded post, I would greatly appreciate any and all feedback. Anyone else experienced a bad GEM timer?

 

Welcome to the forum

Good testing

Test drain with battery saver relay removed, expected is .03-.07amps
Fuses 10 and 20 power GEM but only if key is ON, so these should be 0 volts key off, if there is a problem with ignition switch one could have 12v, long shot

Fuse 25 is the full time GEM power pull it if amp draw is higher to see if it drops

Yes, it does read like GEM is not going to sleep

4 things draw power all the time in a 1999 Ranger
Radio clock/preset memory
Computer KAM, keep alive memory
Keyless entry "watchdog", wakes up GEM if unlock button is pressed
GEM itself, but in sleep mode, waiting to be woken up by door opening or "unlock" from Fob

All this should be approx .07 amp draw, no keyless entry .03-.04 amp

 

Greetings: This thread was very helpful for me. I have a 1997 B4000 and suspect your info about this relay location also applies to my truck. My relay is behind and above glove box. I suspect there are differences with the Ranger, vs Mazda, and maybe even with trucks built for export to Canada.

 

The interior Dome light wouldn't work with Battery Saver relay unplugged, just FYI

 

Could care less about interior light, I have a battery powered motion sensitive LED light stuck on headliner above back window. New technology stops a lot of fustration eh!!

 

Comment was meant to tell you if that relay was for Dome light or not