I have a parasitic battery drain in my 1999 Ford AU, that will flatten a new battery in about 24 hours. I have traced the battery drain to the 40 amp master fuse for the air conditioner. The question is : How can the air conditioner be drawing power even when the ignition is turned off and the key removed? Anyone have any ideas?
A stuck relay will do this.
Testimonial: "Thanks for your help Daniel. I'll give that a try next."
Had a VW jetta do the same thing, AC relay stuck in closed position, allowing constant current flow to AC clutch. replaced this relay and voltage draw no longer there. relay has battery power without key on
DW Mylin
SOURCE: My 03 Silverado has parasitic battery drain. VOM
Disconnect the auxiliary power cable from the under-hood distribution center that runs to the anti-lock brake controller. Remove the ignition relay from this distribution center (this will isolate/eliminate/indicate the problem as the ignition switch). Unplug any GPS add-on device, and any radar detector, stereo amplifier add-on, I-pod, trailer brake controller add-on, anything that did not come on the truck from the factory. These can be frustrating.
SOURCE: parasitic key off battery drain, how to fix
Keep the ammeter in series with the battery with everything off. take out each fuse in turn and note any change to the the residual current drain. The fuse that when pulled out results in a drop in the current drain will identify the guilty circuit. Interior glove box and trunk lights are classics for staying on when they should be off, often the contact brackets get bent and so not longer push the switch as far as they should to break connection. Good hunting
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Thanks Dan. I'll give that a try.
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