Got a '90 964 Cab. Only a weekend driver. Battery is dead from time-to-time.

Yesterday I decided to start the car before the weekend. She started right up after two weeks of non-use. I let it run for 10 minutes and shut it down.

Today the battery is dead (almost dead, just a faint ignition sound). I didn't touch a thing in the car from yesterday's perfect start-up. Something inside is an intermittent short causing a drain.

Any hints on where to start looking? I hate chasing electrical gremlins.

Thanks.

 

How old is the battery ?
And how many times has it been "dead" ?

 

Weird I am having close to the same issue. I installed a new battery in January of this year and I can't figure out where I am losing power? I have the car in the garage and don't lock it.

 

Was it doing the same same before the new battery ?

 

my battery drain came from the heater servos. I replaced them and the drain is gone. A drain can come from many places.

 

New battery a few months ago. I has done this at least three or four times since the new battery.
Old battery had the same problem.

 

In searching the treads in the forum for another similar problem I had, there are, like the other gentlemen indicated, many sources of drain. Two come to mind that are easy checks, the rear lid light, which is easy enough to disconnect and the door switches.

 

Also check the the light in the trunk and clovebox. Open it and quickly check if the light is warm/hot. Common problem.

 

I've had a window switch get stuck in the on position. Might want to check that also.

 

mine was intermittently shorting out -- we figured out that there was a frayed cable next to the starter cradle that was rubbing up against the cradle and causing it to short out. will figure out what the cable actually was attached to and report back - ** this took someone at the old farnbacher loles in ct (a reputable place (before busted for fraud)) days to figure out. The starter had just been replaced. not saying this is a common problem, but if no luck after tracking down all the normal issues, this is one to check out. now i just need to figure out why the a/c wont kick on ..... fuse fine..... compressor still not kicking in...... argh.

 

as mentioned, many possible causes of drain.. . This may be a bit obscure but worth a quick check. I once had a similar intermittent drain issue when the relay that controlled the magnetic clutch of a/c compressor was binding and staying on after ignition off. This relay is in the rear compartment. Of course, other binding relay may be responsible?

 

my battery drain came from the door lights...

I had them turned off, so they never activated when the doors were open. I remembered, before I manually turned them off, that there was sometimes a delay for them to come on... I would open the door and sometimes it would take a couple seconds for the light to pop on...

Overnight battery drain - door light switch