After two weeks of being parked, the car battery drained all the way down. The alternator is good, and the battery is only a year old.

 

The glove compartment may have been left ajar, and I'm wondering if the little light in there could have drained the battery.

 

 

After recharging the battery, I went out with a test light to see if I could find a short. With the negative/ground cable detached from, the test light will come on for a second or two and then go off when I touch the battery cable (or any other grounded part on the car) and the negative terminal on the battery. When I remove both test leads and then reconnect, it will again light up for just one or two seconds and then go out.

 

The tester light is working fine: when I touch the positive and negative terminals of the battery, I get a steady light.

 

So does this mean that I do or don't have a short somewhere?

" The glove compartment may have been left ajar, and I'm wondering if the little light in there could have drained the battery."

 

Yes it could.

 

If I read you correctly ... you are putting the test

light in series with the negative battery cable and

the negative post on the batterry...

This is correct.

 

The flash you see is a capacitor or power supply in

an item (such as your radio or the ECU) charging.

 

Open the glove box door and see if you can see

the test light filament glow.

This will not be very bright as the current is pretty small.

 

Have someone hit the brakes or turn on the parking lights

this will show you what a large current draw looks like.

 

You are sure the virgin switch is not on.

 

What car are we talking about?

 

Hope this helps.

" The glove compartment may have been left ajar, and I'm wondering if the little light in there could have drained the battery."

 

Yes it could.

 

 

in every subaru i have had the glove box light only comes on with the other lights. Check the trunk or hatch light, and the dome lights. check your parkinglight switch

 

nipper

Yes, I connected the tester filament in series with the negative/ground battery cable and the negative battery terminal -- glad I had this part right.

 

The flash you see is a capacitor or power supply in

an item (such as your radio or the ECU) charging.

 

Great info., Skip. I'm glad to know that I don't have to go poking around in the fuse box. Additionally, I'd be curious to know why I get only a flash. Is it the capacitor shutting off after it's fully charged?

 

Open the glove box door and see if you can see

the test light filament glow.

This will not be very bright as the current is pretty small.

 

I wonder why I hadn't thought of this, but thanks to you, I didn't have to.

 

You are sure the virgin switch is not on.

Hope this helps.

 

Nope, I went through that 4 years ago when we first acquired the Forester. Thanks again.

Do you have an alarm or a power amp on this car?

 

 

nipper

@

in every subaru i have had the glove box light only comes on with the other lights. Check the trunk or hatch light, and the dome lights. check your parkinglight switch

nipper

 

This is second had info. from my wife, who was the last to use the car. Perhpaps the car door was ajar and the dome light was the culprit.

If you want to check for excessive draw, you'd want to put a basic digital volt-ohm-meter in series with the battery. Either disconnect the + or - cable, and then put one lead on the battery terminal and the other to the battery.

 

Start at the highest ammeter setting which will probably be 10 amps. Make sure the leads are in the right holes on the meter. If you read less than the next lowest range on the ammeter, which may be 0.4 amps (400 milliamps mA) then you can move down to that range for a more accurate reading.

 

Your typical auto battery might have a capacity of 30-50 amp-hours when fully charged. So if you are reading a load of 0.1 amps (100 milliamps mA), then the battery would be dead after say 50amp-hours/0.1amps = 500 hours = ~35 days. There are other nuisances but this is a simple description.