Battery draining when connected to car.


Asked by Oct 03, 2015 at 10:41 AM about the 1987 Pontiac Fiero

Question type: Maintenance & Repair

Whenever I hook my full, good battery that has no dead cells at all up to the
car, it just completely drains out. No lights or anything are on in the car. Fuses
are good and the relays have been replaced. I'm unable to charge/jumpstart
the battery while it is connected to the car, it will only reach full voltage while

3 Answers

Tom Demyan

You have to test/diagnose the system,


The car has a current leak somewhere. Until you find it and fix it it will continue to drain your battery. Start by measuring it with a meter between the positive battery post and the positive battery cable. You should notice a current flow (amps). Now go down the electrical system until you find out where it leads you for the fix.


A good place to start is to pull fuses at the fuse box to tell when the current stops flowing. When you locate the circuit, then you can start the diagnosis targeting the things that fuse controls.

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