My 98 lumina has a constant power draw from somewhere. I just replace the battery and had the alt tested (it was good). I have to jump the dang thing every morning but if I drive it enough during the day...
The alternator may charge fine but could drain the battery through a bad diode,have you checked the alt for a bad diode?Disconnect the battery positive cable.Put a regular 12v test light between the battery positive post and the positive battery cable.If the test light is bright you do have a drain,if dim it is OK.A dim light may mean the drain is internal in the battery.If you do have a bright light remove a fuse ,one at a time from the fuse box until the light goes dim.Once dim you have identified the bad circuit.If removing all fuses do not dim the light,disconnect the alt charging wire at the alt,if that dims the light,then you do have a bad diode.DO NOT create a drain(bright light) when checking for the drain by turning on the key or opening a door/trunk etc.
Also,do an overnight battery check by disconnecting the battery overnight,if things are fine the next morning after the battery was disconnected then it is a drain in the vehicle,if the battery is dead even after being disconnected overnight,,then the battery is bad.
Jun 15, 2017 |
Cars & Trucks