I'm looking for some help. My 2001 F-350 7.3l is drawing .46 amps when sitting. It drains the batteries in 24 hrs if I dont run it. It has 2 batteries and 2 alternators. I started pulling fuses. Fuse 15 a 5 amp fuse something with the GEM, shift lock and other stuff accounts for about .22 amps. Cant find what else. What should be the normal draw when the truck is just sitting? even .22 seems like a lot for a parked truck.
Thanks

 

I see that you have a GPR LED. Is there any other after market add ons that may be pulling voltage? How old are your batteries and have you had them load tested? Are both of your Alternators working and are they charging up the batteries to keep them up to specs? Two batteries are standard for these trucks, if one is bad it will pull the good one down to its' level. Always replace both batteries at the same time.

 

I'm working through the service manual now for your problem...It says if the parasitic drain is greater than 0.05 amp then there is a problem.

Here is the info from the manual:

Battery—Drain Testing

Check for current drains on the battery in excess of 50 milliamps with all the electrical accessories off and the vehicle at rest. Current drains can be tested with the following procedure.

WARNING: Do not attempt this test on a lead-acid battery that has recently been recharged. Explosive gases can cause personal injury.
REPAIR Circuit 904 for a short to B+. Clear the fault codes and test the system for normal operation.
No REPAIR Circuit 904 (PCM side) from the female side of connector C130 to the PCM. Clear the fault codes and test the system for normal operation.

CAUTION: To prevent damage to the meter, do not crank the engine or operate accessories that draw more than 10A.
NOTE: Many computers draw 10 mA or more continuously.
NOTE: Use an in-line ammeter between the battery positive or negative post and its respective cable.
NOTE: Typically, a drain of approximately one amp can be attributed to an engine compartment lamp, glove compartment lamp, or luggage compartment lamp staying on continually. Other component failures or wiring shorts may be located by selectively pulling fuses to pinpoint the location of the current drain. When the current drain is found, the meter reading will fall to an acceptable level. If the drain is still not located after checking all the fuses, it may be due to the generator.
NOTE: To accurately test the drain on a battery, an in-line digital ampmeter must be used. Using a test lamp or voltmeter is not an accurate method due to the number of electronic modules.

1. Make sure engine compartment and interior fuse panels are accessible without turning on interior and underhood lights.
2. Drive the vehicle at least 5 minutes and over 30 mph to turn on and exercise vehicle systems.
3. Allow vehicle to sit with the key off for at least 1 hour to allow modules to time out/power down.
4. Connect a jumper wire between negative battery cable and negative battery post to prevent modules from resetting and to catch capacitive drains.
5. Disconnect negative battery cable from post without breaking the connection of the jumper wire.
6. NOTE: It is very important that continuity is not broken between the battery and the negative cable when connecting meter. If this happens, the entire procedure must be repeated.
Connect the Alternator, Regulator, Battery and Starter Tester (ARBST) between negative battery cable and post. The meter must be capable of reading milliamps and should have a 10 amp capability.
7. NOTE: If the meter settings need to be switched or the test leads need to be moved to another jack, the jumper wire must be reinstalled to avoid breaking continuity.
Remove the jumper wire.
8. NOTE: AMP draw. Draw will vary from vehicle to vehicle depending on the equipment package. Compare to a comparable vehicle for reference.
No stock vehicle should have more than 50 MA draw.
9. If the draw is found to be excessive, pull fuses from the interior fuse panel one at a time and note current drop. Do not reinstall the fuses until you are finished testing.
10. If the draw is still excessive, then remove fuses from the engine compartment fuse panel one at a time and note current drop. Do not reinstall fuses until you are finished testing.
11. Check the wiring schematic in the wiring diagram for any circuits that run from the battery without passing through the engine compartment fuse box. Disconnect these circuits if the draw is still excessive.

Battery—Electronic Drains Which Shut Off When the Battery Cable is Disconnected
1. Repeat the steps of the battery drain testing.
2. Make sure all doors are closed and accessories are off. Without starting the engine, turn the ignition switch to RUN for a moment and then OFF. Wait a few minutes for the illuminated entry lamps to turn off if equipped.
3. Connect the ampmeter and read the amperage draw.
The current reading (current drain) should be less than 0.05 amp. If current drain exceeds 0.05 amp after a few minutes, and if this drain did not show in previous tests, the drain is most likely caused by a malfunctioning electronic component. As in previous tests, remove the fuses from the fuse junction panel one at a time to locate the problem circuit.

 

Hi Neal, thanks for the handy notes because I think I'm going to need them for my F-150 if they apply.

Does this mean that the cable *can* be disconnected, but just not metered? I'm sure I'm reading that wrong... I'm wondering how I can disconnect the cable and still keep it jumped with that top mounted terminal that wraps around the stud. ???

 

Might disconnect the alternators, one of them could be shorted-out. Disconnect batteries and get them load tested.

 

Thanks guys. It turned out to be a bad battery. It was pulling the other one down with it. Replaced both everything seems fine

 

If you are drawing .46 amp, these new batteries will be old batteries in a few days.

 

I had a battery problem similar to what you're describing about a year ago. It wasn't my solution but one suggestion I got was to put your hand on the rectifier on the back of the alternator (-s in your case). Apparently, alternator rectifiers can develop an electrical fault where they actually can draw current. Put your hand back there when the vehicle is cold and if the rectifier is warm then that's a good indication. Like I said, wasn't my problem but a helpful tip nonetheless.

Another item in my troubleshooting process involved unplugging an aftermarket electronic trailer brake controller. Again, not unheard of for a computerized controller to fail to time out, drawing more amperage over time.

Neal's right, too, the batteries sound like a symptom, not your illness.