Liko

Hey guys. Glad to have found these forums. Anything that keeps my car running long enough for me to graduate will help.

My car's a 1987 Jetta GL 4-banger that's been a trooper until very recently. Started when the battery before last (a Die Hard Int.) died after 2 years (par for the course AFAIK). I couldn't get a Die-Hard from the local mechanic I usually go to, so I went with an International Mega-Tron. 3 days later the battery was dead. I had em replace it, and this new battery died the first time after about a week. They tightened the alternator belt, checked the charge rate, and it should be doing fine all other things being equal. Most of the deaths have been discovered after a cold night, but sometimes the car's failed to start after just a couple of hours. I think the weather's aggravating a grounding problem. After some thought, I've got 3 major suspects:

Radio: Cuts out randomly (can't tie it to any major event, not even a bump in the road). A good whack it gets it going again, so there's almost definitely some loose wires there, either an intermittent contact or a short. This particular radio operates independently from the ignition, so it's the prime suspect.

Dash Clock: Original equipment, and by design does not turn off when you cut the ignition, so if it isn't displaying, the battery is DEAD. 16 years of Texas summers is causing the liquid crystal to leak, and I also get what looks like static if the battery is low. Dunno if this would be a serious enough drain on the battery to worry about.

Wiring Harness: Came loose years ago, was stuffed up into the dash and pinned there with a cable tie. Has been the cause of an intermittently-not-working vent fan, but they tracked that loose wire down. Dunno if they found any others.

Do any of these sound like a serious enough drain on a battery when the engine's turned off? Any other possible causes I need to let my mechanic in on? Remember, the battery's charging fine and all electrical systems work fine when the engine is running. If there's anything you can suggest to keep the car starting regularly on a minimum budget (recently spent $600-something on a new heater core and the battery) till Spring Break, when I can take the car down to Austin and the mechanic that's kept it running this long, I'd really appreciate it.

boschmann

Get an in-line ammeter to measure the current draw. I can probably look up the spec if you need, but it shouldn't dram more than 500 miliamps. If it's more than that start pulling fuses to find where the current is going. A simple battery cutoff switch would solve the problem, but your clock & radio will get reset.

Liko

Thanks for the offer, but I broke down and took it to the local dealership. They charged me $20 to hook it up to the diagnostics and found it was actually the trunk light. I was skeptical; the switch is a pretty simple spring-loaded thing with two contacts and a central plate. Push the piston and the contacts move away, so it didn't look possible to short. But, I went ahead and disconnected both wires from the switch (also dunno why they couldn't have done that) and the battery hasn't dies the last 3 days, in conditions that normally would have killed it dead. So, I'm cautiously optimistic that the problem is solved.