Battery Drain 63 Coupe 327/250

[Tom A.]

New Battery, new cables. After 3 days battery drains so low horn will not honk, if disconnect switch is connected. Have a amps meter, after disconneting the positive cable and attaching meter probes to positive cable and post the drain reading is 6.3. I have run this test by disconnecting, one at a time, the alternator, voltage regulator, and all the fuses. The reading allways is 6.1 to 6.3. I am missing something that is draining the battery. Your thoughts and suggestions are most appreciated. Thanks, Tom Allen

[Edward J.]

Re: Battery Drain 63 Coupe 327/250

Tom, does the car have a aftermarket radio install thats been wired incorrectly, and maybe is wired to 12 volts constantly. I sometimes like to use a test light, as you use the amp meter, is the draw enough to light the test lamp. sometimes things like relays, buzzers, get stuck, clock points or another source.

[Jack H.]

Re: Battery Drain 63 Coupe 327/250

"The reading allways is 6.1 to 6.3. I am missing something that is draining the battery."

Yep! You're assuming that all circuits in the car are switched and fused. That's not true.

There are circuits that are un-switched and run all the time. Like: glove box light, cig lighter, interior lights...

By removing the fuses and disconnecting the alternator, you've only eliminated those specific branch circuits. Now, it's time to trouble shoot the rest. Not to worry, you're on the right track to finding/trapping the culprit(s)!

[Anthony S.]

Re: Battery Drain 63 Coupe 327/250

I would get the clock next = out of the circuit.

[Bill I.]

Re: Battery Drain 63 Coupe 327/250

Tom, if 6.3 means amps, that's a MAJOR draw. Look for something big, like starter, horn relay.Bill.

[Stuart F.]

Re: Battery Drain 63 Coupe 327/250

Make sure you are turning your ignition switch off properly, i.e. to LOCK not ACC (Accessory). I once got confused with our 63 while also driving a Chevy that had a lock position all the way CCW, and was leaving it in the ACC position which was draining the battery. The key will come out on a 63 in either position. To this day I don't know what the drain was from, but I don't turn the key all the way to ACC any more. I even went so far as to suspect a bad diode (leaking) in the alternator, and tested it to be sure.

Stu Fox

[Joe R.]

Re: Battery Drain 63 Coupe 327/250

Tom,

I assume this started when you replaced the battery cables. Well, if that's the case you probably removed the ground wire that goes to the starter and reconnected it to the positive cable of the starter solenoid.

There is a black wire with a white tracer that goes to the mounting bolt of the starter. This is the ground for the heater blower, windshield wiper etc. If connected to the positive connection of the solenoid it will drain the battery thru the coils of the heater motor and windshield wiper motor.

This error has been made by thousands of Corvette owners and mechanics thru the years.

Simple fix and no permanant damage.

JR

[Roger O.]

Re: Battery Drain 63 Coupe 327/250

Tom,

I assume this started when you replaced the battery cables. Well, if that's the case you probably removed the ground wire that goes to the starter and reconnected it to the positive cable of the starter solenoid.

There is a black wire with a white tracer that goes to the mounting bolt of the starter. This is the ground for the heater blower, windshield wiper etc. If connected to the positive connection of the solenoid it will drain the battery thru the coils of the heater motor and windshield wiper motor.

This error has been made by thousands of Corvette owners and mechanics thru the years.

Simple fix and no permanant damage.

JR

Good thought ,he could find out real quick by removing the black ground wires at the blower motor and the wiper motor and see if the draw goes away.

Another thought would be to find the 12g red cabin feed wire at the horn relay and disconnect it and see if the draw goes away.(disconnect the neg battery cable before removing the wire)