big battery drain

[jtdomo]

i took to shop but they couldnt fix it . my voltage meter bounces up and down and a freshley charged baterry only last maybe 1o mins before the voltage drops to about 9 volts. people keep saying something must be grounded but where and how should i look. what could drain it that fast

[grandprixgtx00]

I'm assuming your reffering to the 89 GP in your profile? what engine does this one have??

my first impression would be the alternator. did the shop test the alternator??

[tblake]

best way is to connect a multimeter in series between the battery and the car, set it to amps. Then start pulling fuses and unhooking things until the ampers drop to about 20mA.

[richtazz]

I assume your freshly charged battery has been tested and is good. Following tblakes advice, make sure you disconnect the negative cable and put your ammeter between the negative post and the negative cable. For the battery to drop that fast, you have to have a major draw, like a dead shorted engine cooling fan, alternator, etc... When you get your ammeter hooked up, try unhooking the plug to the voltage regulator on the alternator first. If the draw goes away, the alternator is dead shorted internally.

[brcidd]

I'd be sure to have a 10amp fuse inline with my ammeter- unless you'd like to "let the smoke out" of your meter-- just trying to protect you when you don't know how much current draw you are dealing with.....yet.

[jtdomo]

Originally Posted by jtdomo

thanks i will try that didnt know cooling fan could drain it like that

i pu t a fuse on the fusable link to the alt. but it keeps blowing the fuse what could be the reason

[richtazz]

you have a dead short in the wiring.

[jtdomo]

what is a dead short, it only drains the battery when running what could be the short

[richtazz]

A dead short means that a wire carrying current has worn through and is touching a ground, or the alternator itself shorted out internally and is drawing power rather than generating it. Take the alternator off and have it bench tested as grandprixgtx00 and I have both suggested (many chain auto parts stores will do this for free). If it's dead shorted, it will be very evident during the test.

[jtdomo]

thanks