I have a 94 coupe, 6-speed, and a little over a year ago, I installed a new premium Delco battery. My Corvette is a weekend cruiser so it will sit in the garage for a week at a time. About 2 months ago, I have a Gm/Bose CD/radio unit installed. Since then, if the car sits less then a week, the battery is dead, completely dead, not even any interior lights

I suspected the radio, and tried first, just turning it off with the ****, after turning the car off......no change. This week, I pulled the fuse to the radio, and the battery was dead in 4 days.

My question: How do you go about tracking down an electrical drain like this? I checked the obvious, like leaving the interior lights on, but so far, I can figure this one out. Before the new radio was installed, the car could sit up to 2 weeks, and fire right up, no problems, but not anymore.....anyone got any suggestions? :mad :confused:

 

Most digital multimeters are equiped with a amp meter. Make sure everything is off. Since you know it isn't the lights tape the door switches to the lights off. Remove the positive terminal of your battery and hook the amp meter in series with the postive terminal of the battery. The meter should indicate current drain. Go around pulling fuses and disconnecting electrical add ons until the drain goes away. That will be the currect causing the problem. There is a small drain from the computer and other related items on the car but it is very small. I don't know what current that is but what is drainning your battery will be a miminum of 0.5 amp. Unless of course your battery is toast!

 

1 amp (1000 milliamps) will discharge your battery in 4 days. GM says the leakage current should not exceed 50 ma. My 87 vette draws 27 ma. You need a VOM (volts, ohms, milliamps) test meter which will allow you to measure current being drawn from your battery.
But first, check at night for the vanity lights being on, the console light, the underhood lights. Do you have any aftermarket electronics? radar detector, audio amplifier, burglar alarm?
I recommend you remove the negative cable on your battery (its safer because your wrench can touch ground without causing a damaging short) and place the VOM set to amps between the battery negative terminal and the cable. The meter will read the courtesy light current and the passenger door has to be open to pull fuses, so pull the courtesy light fuse and then begin pulling the fuses one at a time and watch the ammeter (switch the full scale current downward until you can read the leakage current. If the current drops suddenly when you pull a fuse, then further investigation of that circuit should find the culprit. All circuits are not fused, so if the fuse removal doesn't find the current, then you must remove the nut on the jump start terminal behind the battery. This terminal has 8 wires that have fusible links and you should remove these wires one at a time while holding the others in contact with the bolt and watch the ammeter.
Some CFers have found their seat adjust switches were stuck on , so feel the seat adjust motors for being warm. Good Luck.


[Modified by jfb, 7:57 PM 3/26/2004]

 

I'm not sure how yours compares to my "87 but after having no success finding the same problem as you , was standing in garage a couple of hours after driving car and heater fan would randomly start up and run.Needed to replace control module attached to fan housing in engine bay.

 

Use a test light in series with your battery cable instead of the meter if your meter will not handle high amperage. It will glow slightly if the drain is low. If it glows brightly, you have a higher current drain. Then pull fuses one at a time until the light dims.