96 850 GLT .45A Parasitic Draw??

andyleonard · Post by **andyleonard** » 27 Nov 2023, 16:29

Hi, We've been using a battery disconnect since we bought this car 3 years ago for my son, as in 3-4 days the battery will get too low to start the car. Driven everyday it's fine.
Today we went after the parasitic draw and are getting .45A..not milliamps... even with all the smaller red wires removed from the positive terminal. So whatever it is is feeding off the fat red wire that disappears under the engine.
Battery is good and at 12.8V. Charging is good.
Can anyone guess what's doing this? I *could* start tearing the car apart but ..is this common? Is it the diodes in the alt?
Big Thanks,

Andy

Post by **misha** » 27 Nov 2023, 18:20

Time to use a multimeter and pulling out fuses...one by one...untill the drain stops.

Bad diodes would light up a battery warning lamp...even when engine is off.

andyleonard · Post by **andyleonard** » 27 Nov 2023, 18:43

This one has nothing to do with fuses or the smaller red wires. Tried them. I'm getting the .45A from just the fat red wire to the starter area and the ground.

Post by **Chuck W** » 27 Nov 2023, 19:32

That "big fat red wire that disappears under the engine" goes to the starter. (and alternator)

Post by **abscate** » 28 Nov 2023, 01:50

It’s almost certainly a bad alternator diode draw

andyleonard · Post by **andyleonard** » 28 Nov 2023, 07:59

I was afraid of that. I guess I was hoping they picked up power for something else underneath at the starter connection that was unfused.