Current Drain Fuse#11
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Joined: Oct 2003
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From: Michigan
Current Drain Fuse#11
2001 F150SC 4.6L 2WD MT
Hi,
Having a dead (very weak) battery for a few days (1 week old new battery and 2week old alternator) I gave the vehicle to the local guy who could not detect a current draw. I got the battery replaced by was not convinced that was the root cause. I followed some of the diagnostic tips on the other threads to troubleshoot my current draw issue on my battery. Here is how I proceeded:
Conditions Outside Temp ~10F
Start engine, wait till cluster lights go out, turn headlights on then off, bypass neg terminal with wire while engine running while carefully sliding loosened neg battery cable from battery. Enter vehicle, shut off headlamps and remove key then exit truck and close door and lock with key FOB (one click). Verify all internal/exterior lights are off.
This is the Normal Sequence I observed for two of the starting cycles:
Initial Amperage after locking when using FOB: ~1.75A for several seconds,
then 210mA another 0.5 -1 hour
then 12mA for the duration
After two of these 'Normal? cycles I saw a 2.75A draw almost immediately that lasted over a half hour. Thinking I had finally caught the 'gremlin', I started pulling fuses from the underhood fuse box. When I got to fuse#11 (Alternator Field) the current immediately dropped to 210mA and remained there for ~15minutes then dropped to 12mA where it remained. I also should have added that I replaced the #11 fuse immediately but did not see any amperage fluctuations so I left it in.
OK, so I think I got some good data here...and now to call on the 'braintrust' that frequents this forum...can anyone offer some insight on the issue? Thanks in advance.
Hi,
Having a dead (very weak) battery for a few days (1 week old new battery and 2week old alternator) I gave the vehicle to the local guy who could not detect a current draw. I got the battery replaced by was not convinced that was the root cause. I followed some of the diagnostic tips on the other threads to troubleshoot my current draw issue on my battery. Here is how I proceeded:
Conditions Outside Temp ~10F
Start engine, wait till cluster lights go out, turn headlights on then off, bypass neg terminal with wire while engine running while carefully sliding loosened neg battery cable from battery. Enter vehicle, shut off headlamps and remove key then exit truck and close door and lock with key FOB (one click). Verify all internal/exterior lights are off.
This is the Normal Sequence I observed for two of the starting cycles:
Initial Amperage after locking when using FOB: ~1.75A for several seconds,
then 210mA another 0.5 -1 hour
then 12mA for the duration
After two of these 'Normal? cycles I saw a 2.75A draw almost immediately that lasted over a half hour. Thinking I had finally caught the 'gremlin', I started pulling fuses from the underhood fuse box. When I got to fuse#11 (Alternator Field) the current immediately dropped to 210mA and remained there for ~15minutes then dropped to 12mA where it remained. I also should have added that I replaced the #11 fuse immediately but did not see any amperage fluctuations so I left it in.
OK, so I think I got some good data here...and now to call on the 'braintrust' that frequents this forum...can anyone offer some insight on the issue? Thanks in advance.
Last edited by herf; Jan 17, 2009 at 04:51 PM. Reason: Additional Info
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Joined: Jun 2002
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From: Under the flightpath of old ORD 22R
Might be worth having the alternator tested.
With the Ign input to the alternator is working correctly, but the regulator is not shutting down when the ign input is removed ?
The alternator test show show if with the ign terminal off, there should be little voltage ( mV range ) on the regulator terminal. Once ign is applied to the alternator, the regulator voltage level should raise to ~ battery voltage level.
These are really just SWAGs right now, but starting with an alternator test is a god place to start with this I would say.
With the Ign input to the alternator is working correctly, but the regulator is not shutting down when the ign input is removed ?
The alternator test show show if with the ign terminal off, there should be little voltage ( mV range ) on the regulator terminal. Once ign is applied to the alternator, the regulator voltage level should raise to ~ battery voltage level.
These are really just SWAGs right now, but starting with an alternator test is a god place to start with this I would say.