Amp draw at rest (speedo/GEM)

[thoncom]

After minutes for allowing the vehicle's electronics go to sleep a .17 amp draw remains present. Found circuit on fuse #25 to be the culprit -- a 7.5a fuse which drives the speedometer and GEM system. A search didn't uncover this as a typical issue, hoping someone can offer a bit of insight. I understand GEM is a module but not sure if the speedo reference is inclusive in the GEM or separate (one or two possible targets for inspection or replacement).

This .17a draw would not be a problem if the truck were a daily driver but it can be weeks between diving and even a new battery can't seem to keep up.

 

[Snoranger]

Fords spec for parasitic loss is .05 amps. It can take older vehicles 15-20 minutes before they go to sleep. New ones can take 45 minutes.
We have a fleet of Fords at work (about 1200 currently), it’s not uncommon for the dash cluster to cause a parasitic loss.

 

[RonD]

Yes, normal draw after 30min or so is 0.03 to 0.07amps, 30 to 70mA, 70mA is if you have Keyless Entry it has to be "awake" all the time

1996 has the GEM behind the radio, its what "goes to sleep" after 30+ minutes
You could pull the radio and bezel then unplug all the GEM connectors, GEMs for sure asleep now, lol
Then retest amp draw
If still high then cluster is the problem, cluster can be replaced with 1996 thru 2003, plug and play
If amps drop to normal then could be GEM timer issue

 

[thoncom]

Much appreciate the quick and insightful replies!

Hopefully I'm not allowing enough time for a definitive draw test and the problem is simply a defective new battery. Will give it at least an hour and if an out-of-spec draw remains I'll inspect further based on the provided suggestions.

 

[RonD]

Also, after battery has been sitting at least 4 hours(engine off), disconnected either cable(or both), test its voltage, WRITE IT DOWN, i.e. 12.6volts
Test it again after 8 hours, the longer it sits the better, 24/48 hours
Should have EXACTLY the same volts, i.e. 12.6volts
If so battery is OK
If its lower, battery is Self Draining, has an internal short, most common failure for any car battery, new or old


Car Batteries have many thin plates sandwiched close together, they trade electrons when discharging and recharging
Over time they can build stacks of electrons between the plates and if the stacks ever touch, self draining occurs
Overcharging or full draining will warp plates, if they touch self draining
Debris left in a battery after rebuild or new manufacture can short plates

 

[thoncom]

Thanks for the additional input RonD!

A fault of mine (and many) is that I don't always take the path of less resistance (pun ?). Since this vehicle is not a daily driver I could have performed your mentioned test on the battery prior to testing for and assuming a draw on the system. I should know from experience new doesn't mean infallible.

LOL. With the current state of my memory, yes, I'll write it down. ;-)

 

[4x4prepper]

Solar charger on the dash board (not a Chinzy lighter deal) wired directly to the battery or battery disconnect manual or remote relay. You need to solar trickle 13+ volts, not 12v.

.17 x 24 (hours) x 7 days = 29 Ah. That will knock down a battery some.

My daughter killed her battery by leaving one of those $12 Chinese LED volt meters that plug into the lighter, in for two weeks while on vacation.

 

[thoncom]

Wow, I know, I'm a procrastinator. Cant believe it's been a year since the last post. Figured I'd provide a final update (sans a proper correction to the complaint & cause). ;-P

The draw remains isolated to the spedo/GEM circuit and as I only use the truck every couple of months took the easy route and installed a battery terminal disconnect. The inconvenience is minimal and now, instead of the battery being too drained to start the vehicle in as little as two weeks, it cranks to life easily after more than three months of inactivity. I know a trickle charger should be employed considering excessive months of disuse but I'm hoping the lack of will spur me to get it out on the road a bit more.

Thanks!