Originally Posted by
zj93i6
For the better part of two years I have had this problem. If I don't drive my 2005 at least once every two days, on the third day the battery is dead. I have put a meter on and get a .4 milliamp reading, pretty normal.
400 milliamps is normal for the first 30 seconds or so, but then it should drop to under 55 milliamps.
.4 amp is 400 milliamps. Anything over 55ma (.055 amp) is too much. With .4 amp I'd expect the battery to last MAYBE 36 hours.
- Disconnect the battery ground cable, insert an ammeter, and start pulling fuses until you find where the current is going.
- Start in the little box next to battery. Pull each 50 amp fuse, if the current is still there, pull 200 amp fuse.
- If 200A makes it go away, put the fuse back and go to the main fuse boxes and start pulling fuses (box next to brake controller, then go to fuses on the Relay Control Board, then go to fuses in the ICM, driver's end of instrument panel.)
- If the 200A being out does not make it go away, it's the alternator or starter (which means it's the alternator).
- Disconnect the big fat red cable at the alternator - if the current goes away, replace alternator
REMEMBER that the current will be high when you first connect the meter or insert the 200A fuse. Stand there,
wait at least 90 seconds each time for all the modules to "hibernate". After 90 seconds, you should see .055amp or less.
REMEMBER, doors must be closed, trunk must be closed and key
NOT in the ignition.
REMEMBER that taking the car to almost any garage/dealer for a battery drain issue is a waste of time because NO ONE is teaching electrical troubleshooting these days. I once worked for a Motorola radio shop, we got cars from dealers often with battery drain issues. I usually could find the problem in 1/2 hour. I either fixed it or, if it was an OEM module, I'd just inform the garage/dealer which module to replace.