moveon622

Traded the Harley Road king for a 79 c3. I am having a battery drain issue. I have read the forum with this issue and have gone through the tests. With a test light in series with the Neg battery cable and the courtesy light timer removed I tried every fuse and still had the test light on. Next I started to unplug harness's under the hood until the light went out, There was one harness near the firewall by the light switch for the hood light with 5 wires. when disconnected the light went out. next I jumped one wire at a time until the light came on. there were two wires that caused the light to come on. Both of them go down to the starter/solenoid. Does this mean there is a problem in the starter and/or solenoid ?

Big2Bird

What color wires?

moveon622

All red had a real bright light. Red with black stripe had a somewhat dimmer light

'75

Those wires are getting power from the starter, so unplugging them kills the power to the whole car.

'75

Do you have a schematic?

moveon622

So are you saying that would have nothing to do with my drain issue ? Other than it is supply all power to the car so of course when it is unhooked there would be no drain.
any ideas what I can do to find the issue ? I can add a switch on the neg. battery cable which will of course stop the drain but it does not really tell me whats bad and I would rather get it fixed before I add the switch

moveon622

no I do not

'75

If you PM me your e-mail, I will send you an electrical schematic. There are numerous possibilities for your drain, sounds like you have eliminated a lot of them. The alarm system is a common source of drain on these cars also.

moveon622

PM sent

Richard454

Here's a PDF you can download for a 79-

http://www.keystonestatecorvetteclub...tte%201979.pdf

The wires from/to the starter -actually goes directly to the battery - that's not going to indicate anything.

You really need a VOM meter not a test light- Can get a decent one for $25-50. You need to check current draw- not whether or not you are seeing voltage.

You'll put the meter in a series between the negative battery terminal and the neg cable.

Here's a good video-

moveon622

When first hooked up the meter reads 2.38 amps once the courtesy go out it drops to .38 amps

Richard454

That sounds about right for the interior lights to pull that much.

When it drops down to less than a ½Amp - that's not too bad- on a good battery it'd take about a week or two to wipe the battery out.

Try pulling the 20A fuse- "Cig-Clk"- and see if that solves it. Then you just might need to replace the courtesy light timer (behind the glovebox)

If that doesn't solve it-Do you have an aftermarket alarm or radio?


Let us know-

Richard

moveon622

It will only take over night or maybe a day before it is too low to start the car. The battery is new and has been tested. There is an aftermarket Radio in there. I tested with a light (but not the amp meter) yesterday with the clock and light timer removed I still had the the light lit up but I do not know how many amps it was pulling at that time. I installed a cut-off switch for now so it wont keep killing the battery but I would like to find the problem and fix it right.

speedreed8

unplug the alternator. Could possibly be bad diode

Andredechimpansee

Hi,

Did you find the problem?
I have a 79 L82 with the same symptom.
Did not install kill switch, but disconect + from the batery...
Cheers.

Crusader998

I found 2.3amp drain when I left the manual wiper override switch on(the twist switch under the dash on drivers side). It seems to drain power even though nothing is happening and nothing is plugged in so that might be a simple thing to check!

Cool bean

Speedreed8's got it. I had the same issue and went through the same diagnostics. The test light only went out when I disconnected the alternator. (With car not running.)

i had just had the alternator rebuilt at a local shop. I took it bacl to him and he repaired it right in front of me. I took it home, installed it, and drain issue was gone.

hope this helps.

moveon622

No I did not. Have been really busy and have not had time to look at anything for a while

Cool bean

if you want to test and see if the alternator or the diode in the alternator is the problem, leave all wires connected comma including the test light between the negative terminal and the negative battery cable. Then disconnect wires from alternator. If light goes out the alternator is the problem.