Parasitic Battery Drain
 

My 2002 Ford Ranger has developed a 210 ma parasitic battery drain. So, I hooked up my multimeter and pulled each fuse one by one and Fuse 26 is the culprit. This fuse protects: Battery Saver Relay, Auxiliary Relay Box, Restraint Central Module (RCM), Generic Electroic Module (GEM), Instrument Cluster. Any ideas where to start here on isolating which of these components are involved? I'm suspecting the instrument panel, which would be a nightmare to do anything about.

I would suspect one or both of the relays first. Pull one, then the other and measure the draw.

Fuse 26 will always have a bigger draw for 20-30min after key off doors closed
GEM module controls battery saver relay and remains on for 20-30min, has internal timer, then turns off battery saver relay after 20-30min and GEM goes to "sleep"

Spec amp draw in a Ranger with keyless entry is 70mA, 0.07amp, no keyless entry, 40mA
Pull fuse 26 and see what the amp draw is
Computer, radio(time) draw 40mA, keyless entry(Fobs) draw 30mA

Batteries become self draining, so will go dead after sitting overnight or a few days
Test the battery first
Unhook a battery cable, doesn't matter which one, or unhook both
After battery sits for an hour test its voltage, WRITE IT DOWN
Then test voltage again after at least 4 hours, overnight is better, 8+ hours
If voltage is lower then battery is self draining and needs to be replace, even if brand new

Thanks for responses. RonD I checked the battery and it is holding the exact charge for 48 hours. Yadkin, since learning more about the causes, I've been able to search them on this forum and discovered that just replacing a relay doesn't usually address the issue since everything covered by that relay could be the problem. Although I could repair accessible wiring issues, pulling dashboards, diagnosing GEM issues, etc are beyond my competency level.

A relay is a remote controlled switch; nothing more. When it's off it should be completely off. As they age, this may not be the case.

Battery saver relay doesn't "cover" all that much, just interior lights

Pull out Battery saver relay
Insert fuse 26
Test mA at battery, if its 40-70mA then yes problem is an interior light, but that should be cut off after 30min so wouldn't cause dead battery
if you sitll have the 210mA draw wait, with key in your pocket and doors closed, for 30min see if it drops, that's the GEM "going to sleep"
If it doesn't drop then GEM is the issue, its not "going to sleep"
If draw does drop but not to 40-70mA then instrument cluster or Restraint control module is the issue, you will need to unplug each and test mA draw

I'm just getting back to this problem. I can't seem to find the location of the Battery Saver Relay or Auxiliary Relay Box. I'm using the diagrams on 2002 Ford Ranger Fuse Relay and they don't exactly match what is on my truck. I've attached photos of the three possible locations. The third photo is the possible location of the under dash relay box behind the radio/heater/dashboard. Can someone confirm if this is the location of these relays and if they can be accessed/removed without removing something other than the cover? Also, how do you get the cover off? My experience has been that if those are tabs that they tend to be very brittle and often break off. Do I just stick a screwdriver in there and twist?????




https://cimg4.ibsrv.net/gimg/www.ran...b071ce97bf.jpg
https://cimg5.ibsrv.net/gimg/www.ran...c86eb63da5.jpg
https://cimg6.ibsrv.net/gimg/www.ran...06a91550e6.jpg

Last picture looks like it, take the cover off of it, its just above gas pedal area

Can look like this with cover off: https://f01.justanswer.com/D1Fl5whp/...lay_box__2.jpg

What each relay does varied by options in the Ranger, so there is no exact "map"

Here is one version: https://ww2.justanswer.com/uploads/b...3_Capture1.PNG

Do I push in on that tab to release it or push it out? I can't view the clasping mechanism.