I've got a battery drain coming from somewhere, and I got a test light to check it, but I can't seem to figure out how to put it in line with the battery. I've read that it should go between the harness and the positive contact of the battery, but it doesn't seem to work. Does it matter whether the black end clips onto the harness or the battery? And yes, the battery is fully charged. Made that mistake a couple days ago...

The grounds are sparkling clean, as well as the contacts. There'* a good chance that I have a corroded cable (antifreeze leak last year at the water pump fitting), but I'm going to figure out how to check that after I eliminate a low drain from something pulling power. Alt is less than 6 months old, battery is 1 month old.

Thanks for your help!

Test light won't really help much. Need a digital volt meter. You need to see the voltage increase when you start pulling fuses one at a time. Or an ammeter will work.

Depending on how much power(amps) your problem is pulling, your test light might act like a fuse and just blow the element in the bulb if you use it inline with the battery.

I'll try that, I do have a little Harbor Freight voltmeter. How do I connect it into the system to check for draw on the battery? I'm really bad with electrical stuff. My voltmeter comes with two little pointy ends. Should I get one with two clamps, and attach one end to the positive terminal on the battery and one end to the harness? Is that how you set up an inline test?

Does your meter have the capability to measure DC current? If it does, configure the test leads for measuring DC current by placing the leads in appropriate jacks on the meter. Select correct scale on meter then connect the meter in series between the battery positive post & the battery positive lead that you disconnected. Do not turn on any large loads with this lash up in place. Monitor current flow with ign. off, key out of ign. switch.

So now I think I have more questions than answers...

I rigged up the voltmeter inline with the positive terminal. Once I got it connected, before I shut my drivers side door, I remembered that I had pulled the 60A ignition maxifuse the night before. When I put it back in, the dashboard started dinging like I had just started it up. The keys were on the radiator in front of me, not in the ignition. I thought that maybe some power surge had triggered the remote start, so I pulled the tester off, and cut the power. When I reconnected the battery again, it was fine, no dings. Is that normal?

Once I got the door shut, the tester showed a draw of only 0.04 A, which I don't think is nearly enough to be killing the battery every couple of days. I thought for a while that when my antenna occasionally snags a twig as it'* closing, the motor was killing the battery, but it'* since died without any branch in there.

Any new ideas out there for what I can check? Could this be a corroded cable? I cleaned all the contacts until they were sparkling clean last month, posts, grounds, everything.

I'd disconnect the power wires going to the antenna.

I had a problem like that in my 71 AMX, which turned out to be a battery with an internal short - a real pain to find! and another problem like that in my 74 Capri which turned out to be the glovebox light not going out when it was closed.

Also you might want to check the ELC pump. I think I remember reading that in some years its always live so If your struts leak it'll pump 'em up in the middle of the night, all night long.

.04 Amps might just be enough to kill your battery. How long is the system at idle for between start attempts that it is draining enough to not start?

The 40 ma draw that you have is above the recommended maximum of 30 ma that GM lists. The typical listed draw is 7 - 12 ma. The example they use is a 30ma draw will discharge a fully charged battery to the point where it can't start the car at 23 days...65% (green dot barely visible) 15 days.

plus, if the battery is old, or has been fully discharged and stressed severely, it will not hold a charge like that of a healthy battery