Stearmandriver

The car:1993 964 C2
the problem: The battery seems to drain down after a few days of just sitting.
the question: Does anyone know of any causes of this drain.
thanks,
David

crg53

First off I would check all the lights i.e. frunk lid light, engine lid, interior, glove box light, make sure they all shut off when closed. Frunk, engine and glove box are the hardest to check, but if you open them quickly and then feel the bulb it should not be very warm, or you can remove the bulbs and see if you still have a drain.

Grazie

Another testing approach....perhaps unnecessarily high tech....I started the video camera on my cell phone, put it in the glove box and closed it, waited, opened it then checked the film :-)

re: battery drain, there are quite a few threads on this too you might check out (search: battery drain). I tired a good number of tests to no avail....though my battery drain problem seems to have subsided. Only thing I can think of is my removal and replacement of the door open/close switches and/or hood lid switch might have freed up a sticking one. Seems okay for now though unsatisfying to not be able to confirm root cause.

Vandit

Make sure your dome lights are set to turn on when your doors open, then make sure your dome lights are actually turning on when you open the door.

I had a driver's side door jam switch that was sticking and not registering my door opening after turning off the ignition. The result is that the power windows will stay powered and drain over 200mAh, killing your battery in ~2 days.

Happened to me.

Henry964

My car is similar to yours (same model, same year) after being plagued with dead batteries after a couple of days of not using the car, I installed a battery cut out switch and my problems are gone, is the fist time in 4 years of ownership that my battery is more than one year old and keeps working fine.

And yes, three different Porsche shops checked my car for electrical problems, before I decided to stop it once and for all.

c didy

do you use something to save all the memory every time you use the cut off?

http://cgi.ebay.com/ebaymotors/Car-M...-/160056386071

deutschland-dobson

Interesting idea that, I wonder how long the radio and clock etc would last on a 9v battery with a battery drain?

Chris

Henry964

I don´t use anything to save memories, I just put the clock on time and reset the 2 radio stations I like to hear (classic rock) and that´s all

Rocket Rob

I had a similar problem. The method for finding the problem is not hard but it can be tedious. First check for the simple things. Are the door, hood and engine cover light switches operating? If not, the interior lights will stay on. Also check the glove box light. Also confirm your battery is good. With the engine off, you should have 12.5 volts and with the engine on, you should have 13.5 volts.

If all of those are working, next get a volt-ohm meter (VOM). Connect it in series in AMP mode between the battery negative terminal and the ground cable. Also have all doors and engine cover closed and disconnect the trunk light. Measure your current draw. A normal 964 will pull about 40-60 milliamps (ma). If your battery is going dead, chances are, your number will be much higher.

Now start pulling one fuse at a time. Watch the VOM. When you pull the fuse where the problem is, your current draw will drop dramatically. In my case, My car was drawing 1.5 amps and and it was related to fuse #2. I then used the electrical diagrams to find what was on that circuit. It was caused by a faulty CCU.

Good luck and let us know what you find and if you need any more help.

Vandit

When testing for draw, make sure you're not breaking the circuit on the battery since most draws will die if you break the circuit.

Using a normal 2-pin amp meter, I was able to maintain the circuit by putting one lead on the post and another on the terminal while connected, then I'd slowly raise/disconnect the battery while always maintaining contact w/ the pins.

If for whatever reason you do break the circuit, then you need to set the ignition to on then off in order to restart the drain.

robingb

i had same problem that is now fixed. after getting out of car with window 1/2 done reach in an see if windows are still powering up and down. if so, problem is with door connections. you might also check related relay to see if it is hot. good luck, gary

BHMav8r

Amp meter will find the culprit.

Mine was a hidden aftermarket anititheft GPS unit similar to lojack.

However, these cars seem to draw down in about two weeks. Unless you drive it every three or four days you need a trickle charger. Plug into cig lighter is convenient.

Babalouie

Yes I have a lojack as well, my draw is about 250mA (in comparison leaving the interior dome light on is 1000mA)

Stearmandriver

thanks all. I'll try these tests and let ya all know what I find.
David

bmohr

I have a large draw that depletes my fully charge bat in 2 days. I have traced it to the number 1 fuse. So, any ideas what that means? Is the blower solenoid stuck in the ON position. How do I resolve that if so? I'd hate to have to pull the dash. For now I just removed the fuse.