dunndt
New Member
when i leave my car on for an extended period of time the battery will die how do i figure out where the power is going when it is off no lights are on that i see and nothing is audible what could it be
batery dieing
- Thread starter dunndt
- Start date
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NOTAURIUS
SHO Member
if it is dying with the key off, you can check for parasitic drain by disconnecting your negative cable and hooking a multimeter in. Put one prong on your neg batt terminal and the other on your neg cable. I think you should get like .05 volts. Someone correct that reading if its wrong.
projectSHO89
SHOless In St L
I just fixed the neighbor's old Cavalier yesterday that was doing the same thing.
I made sure that all visible couresty lights were off, cheated the door switch so I could keep the door open with no lights, unplugged the negative cable from the battery, and inserted my handy Radio Shack Autoranging meter, set to the 10A current scale.
His car was measuring about 250 mA with nothing on, it should have been 1/10th that. Started pulling fuses until the current dropped to near the expected value. That isolated the circuit, his happened to be the courtesy lights fuse. Opened trunk, no light. Opened glovebox, light was on, current through the meter didn't change (it should have gone up by the amount drawn by the bulb). Pulled the bulb, current dropped to expected. Closed glovebox, current stayed. Put bulb in bottom of glovebox , told him he needed a new switch. He said he didn't need a glovebox light. Reconnected battery, charged overnight, job done.
I worked on an 85 LTD last month with the same problem. Did almost the same procedure to try to find his problem. Pulled every fuse, no luck...constant 2.5 Amp draw. Finally had to cut wires to isolate to the individual circuit. His happeend to be a shorted EEC power relay. 3 bucks at the junkyard, put a couple splices in, and reconnected everything. Charged up the battery and closed the job.
Moral of the story... measure the current being drawn from the battery. Remove loads until the draw is normal to isolate the circuit. Just remember that there are several loads that always draw current. These include the radio memory, the clock, and the EEC KAM (keep Alive memory). These should total less than 25 mA.
Good luck.
Steve
I made sure that all visible couresty lights were off, cheated the door switch so I could keep the door open with no lights, unplugged the negative cable from the battery, and inserted my handy Radio Shack Autoranging meter, set to the 10A current scale.
His car was measuring about 250 mA with nothing on, it should have been 1/10th that. Started pulling fuses until the current dropped to near the expected value. That isolated the circuit, his happened to be the courtesy lights fuse. Opened trunk, no light. Opened glovebox, light was on, current through the meter didn't change (it should have gone up by the amount drawn by the bulb). Pulled the bulb, current dropped to expected. Closed glovebox, current stayed. Put bulb in bottom of glovebox , told him he needed a new switch. He said he didn't need a glovebox light. Reconnected battery, charged overnight, job done.
I worked on an 85 LTD last month with the same problem. Did almost the same procedure to try to find his problem. Pulled every fuse, no luck...constant 2.5 Amp draw. Finally had to cut wires to isolate to the individual circuit. His happeend to be a shorted EEC power relay. 3 bucks at the junkyard, put a couple splices in, and reconnected everything. Charged up the battery and closed the job.
Moral of the story... measure the current being drawn from the battery. Remove loads until the draw is normal to isolate the circuit. Just remember that there are several loads that always draw current. These include the radio memory, the clock, and the EEC KAM (keep Alive memory). These should total less than 25 mA.
Good luck.
Steve
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