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Big Parasitic Drain

2K views 4 replies 3 participants last post by  mddombrowski 
#1 ·
04 Rainier. 5.3 awd. Has roughly 3.4~3.5a parasitic draw.

I've disconnected the alternator and pulled every fuse in both panels to no avail. Are there common areas/issues with shorts or drains that wouldnt be identified via pulling fuses? Any ideas on where to start looking?
 
#4 ·
Then the only thing I see that could be left are the cable to the starter solenoid, the alternator which you say you have already disconnected rather than unbolt the big fuse, and the cables to the 2 fuse boxes. I would have thought, though, that any problem with the 3 power cables would have caused a fire before now. Certainly more than 3.5 A. And I am assuming from your 3.4-3.5 that it is a constant draw which is unlikely for any wiring failure.

Next step might be to isolate which fuse box is passing the current by disconnecting each entirely.
 
#5 ·
I'm assuming you have either an amp-clamp or at least a multi-meter capable of measuring milliamps?

There's only a few things that draw whole amps like lights, pumps, and motors, but the process is the same.

Put an amp clamp around the positive battery cable. You need to wait for all the modules to power down. Acceptable power draw is 50mA (0.05A). Start removing fuses, one by one, until you find the fuse that affects the amperage reading. Grab a wiring diagram and start tracing that specific circuit.

If you open any of the doors or hit the keyless entry, the entire system wakes up and you'll need to wait for it go power down again before continuing.
 
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