constant drain
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New User
Joined: Dec 2010
Posts: 2
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constant drain
anybody good with wiring?when i disconnect the - cable and put a light tester between the negative cable and the negative post it lights up real bright then dims down but stays on.i have replaced the alt.,voltage reg.,wiring harness,.plese help about to go CRAZY!!!!
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
If EVERYTHING is off, the light shouldn't light up. But if something is drawing current, the light will shine.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Start pulling fuses until the light goes out. This will isolate the circuit. If the light doesn't go off, then the short is somewhere else: a circuit protected by a fusible link, headlight circuit, voltage regulator, etc.
Cargo Master
Joined: Oct 2010
Posts: 2,674
Likes: 16
From: Ideeho
Just a quick FWIW.........I had a draw on mine too. Turned out to be that the dome light switches on the doors were so corroded/rusted that they were providing continuity at times. Sometimes the dome light would shut off sometimes it wouldn't.
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Posting Guru
Joined: Sep 2009
Posts: 1,159
Likes: 1
From: Suburbs of Chicago
x2 on the pulling fuses technique.
Also, do you have good brake pressure? If not, the brake pedal will sink and complete the circuit to the taillights even if the truck is off.
Also, do you have good brake pressure? If not, the brake pedal will sink and complete the circuit to the taillights even if the truck is off.
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MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
You need to remove the fuses one at a time, not unplug things. Do this until the fuse panel is empty. If the light goes out, report back with which fuse put the light out. If the light does not go out even after the fusel panel is completely empty, then we'll go from there.
Tuned
Joined: Jan 2009
Posts: 457
Likes: 7
From: Decatur, AL
The alternator has three diodes in it. They act as one way check valves. When one goes bad, the current will reverse flow and pull the battery down over night.
R&R the Alternator and have a shop check it out. Or drive it up and have them check it out. Make sure whomever does it at least knows what you are looking for.
R&R the Alternator and have a shop check it out. Or drive it up and have them check it out. Make sure whomever does it at least knows what you are looking for.
