While trying to find a battery draw in my car today, I disconnected the negative battery cable and placed a test light between it and the negative post. The light lit bright which according to what I have been reading would indicate an electrical draw. I removed the ACC 20amp fuse and found the test light was no longer lit. Now what do I do to find the culprit? The car is an 87 IROC convertible with a stock 305. I did find a proximity sensor taped to the hump underneath the center console. The 3 wires on it were cut clean. Also, when I bought the car, the front fog lights were cut, the rear hatch motor was disconnected, the cigar lighter was unplugged and the underhood light was without a fuse. This leads me to suspect an electrical problem the former owner "forgot" to disclose when I bought the car.

 

The only thing I can think of that should be drawing power when the switch is off would be the radio clock.

 

start cleaning grounds and checking the total run of power wires for cracked and exposed insulation were the wire could be touching metal

also use a test light and check all the cut wires to see if any of them is touching metal

 

I'd check all the circuits that are powered by the ACC fuse:
- courtesy lights - you'd see them lit
- door locks - you'd hear them move
- cigar lighter - unplugged
- hatch release relay - N/A
- tonneau release relay - status?

When you pull the fuse and reinsert it, do you hear any noises? Clicking? Whirring?
Is there an aftermarket amplifier/radio in the car that could be miswired?

If you had a dead short, you'd be blowing fuses. But this is a steady small draw which means there's a device on that circuit that we're forgetting.

Are the horns disconnected? The horn relay is powered from this circuit.

Lou

 

The tonneau conve does pop although requires a little push down on the drivers side to fully open. The cigar lighter is plugged in just not connected to the silver chamber that holds the heating element you push in to light up a smoke. Horn is connected, when I push it or even tap it it blows, its very sensitive. I did change the steering wheel back to being original, I wonder if somthing is touching inside there. The stereo is stock, no amps. I did not pay attention to any noises when reinserting the fuse but sure will today and post back tonight.

 

The cig lighters are notorious for causing electrical acc lead circuit faults. Since yours is un-pluged.. Pull the housing and test it with an ohm meter. If it faults to ground all of the time, it's bad and may-be a major player in what might otherwise be a simple fix. Give it a shot.

Good luck

 

youll have to forgive me, Im still learing as I go. I do not understand what you are explaining. Could you tell me how to pull the housing and test it with an ohm meter? How do I know if it faults to ground all the time? I have a digital multi meter that I bought from harbor freight. Will this tool perform the test you describe? Where do I hook the leads and to what do I set the dial?

 

Messed with the car again to find this drain! I inserted the 20amp fuse and listend carefully for any noise. The only thing I was able to hear was a faint zzzz noise that last only a second or 2. This noise was comming from the area of the radio. I removed and inserted the fuse several times to pin point the sound. On a couple of occasions, the radio made a noise that kinda sounded like a cassette tape comming to an end and changing sides. There is no tape in the radio and it does not appear the heads are spinning with the fuse in.
I reconnected the test light to the negative cable/post. With the 20 amp acc fuse in it
was lit. I began pushing buttons on the stereo, power windows and jiggled the cigar lighter while watching the light and nothing changed. However, when i pressed the tonneau switch as if I were opening it, the light would become noticeably brighter. Could this be a clue? The tonneau switch is operational, I am able to use it to pop the solenoid.