ABS light comes on and then car dies.

Question

We replaced the alternator in our 1996 Olds Cutlass Supreme, as well as the battery and the starter last week because our car was dying every other day. This morning it died again. Whenever the ABS light comes on, it dies and then clicks when we try to turn the key, only starting when it gets a jump ... Almost like a battery drain. Our new battery tested okay. Could a fuse or a relay be bad?

Answer 1

you've got something in the car that is staying on and draining your battery.  typically it would be a underhood light, the light in your trunk, an interior light such as a dome light or glove box light or a radio.  

the other possibility is that you have a bad diode that is allowing the current to flow out of the battery when the ignition switch is off

The problem is not with the ABS system; the reason that light comes on is that it is the lowest voltage circuit in the car and when the battery doesn't have enough electrical energy to power anything else that's the only thing that will work before the battery is drained.  don't waste your time trying to find something wrong with the abs as its not the problem, only the symptom

the only way to find it is to use a amp meter connected in series between the battery positive cable and the battery post then removing each fuse in the fuse box until the circuit that is pulling the charge out of your battery is identified.  then you can check the items on the circut to find out what's staying on.    if, after pulling all of the fuses the current draw is still there then the problem is with a bad diode.  A diode is a one-way electrical switch that when it fails will cause the current to flow in the other direction and drain the battery.

if you don't have an ampmeter start with the obvious suspects--remove the light bulbs from the under hood lamp and the trunk lamp as well as the dome light and the glove box light (if you have one) and see if the battery continues to drain down.  if it does, chances are you have a bad diode and you'll have to take the car to a mechanic for further diagnosis.

hope that helps