lina944

Hi all,

I'm hoping you can help me out with the battery drain on my 944.

I've pulled all fuses and relays, to no avail.
Currently, the battery is drawing about 47mA. I know Clark's garage says 65, but I see other cars getting around 10. So what's the deal?

I've checked interior switches (door, glovebox, rear hatch) and nothing.

I also got the alternator/charging system checked today and nothing. Also, my battery is new (I keep getting a replacement when it goes dead...)

Any help would be appreciated!

Lina

lina944

One more thing - the culprit is coming from the three wires connected to positive terminal. It is shorted to ground, about ~175 Ohms. The other cables (starter/alternator) aren't shorted. Also, nothing else is coming off the battery directly (i.e. aftermarket stereo).

marc abrams

Which wire? One goes to the DME relay and the other two is your #30 bus which goes thru out the car powering anything that's constant power. Pull the relay and then each fuse until the draw goes away.

mytrplseven

One common source of this problem is the factory alarm system. I don't know if that's your issue.

lina944

Thanks for the responses.

I checked out the schematics and did see the wires go to the #30 line. But I can't seem to find schematics for a late 944, which only has the one fuse box.

I'm trying to track down anything that's coming directly off the #30 line that doesn't link to a fuse or relay (as I've pulled all those, with no effect)

Any insight on this?

Humboldtgrin

Disconnect the ignition switch connector and see if that does anything.

gtroth

Are you saying that your current drain, which sounds normal, is killing new batteries?

marc abrams

Gtroth is correct, 47ma shouldn't drain the battery. It would take a month at that rate. But 47ma is a bit high for a 944 electric system.

I've should have been more clear about the #30 bus line. Those two wires (#30 bus) feeds the ignition switch and headlight switch (both not fused), and the fuse box. And if you was to remove every fuse and relay from the car, any terminal or fuse holder that was still getting power throughout the car (except for the DME relay, starter, alternator terminals) would be part of the #30 bus line.

jpk

get a trickle chager (battery maintainer) and be done with it. The battery in my 968 is almost 10 years old at this point; no signs of any problems. I plug the maintainer in via the cigarette lighter whenever the car is parked. I occasionally blow the 15amp cigarette ligher fuse if I pull the lighter plug out before unplugging the charger, but beyond that it has not been any hassle.

lina944

I'm pretty sure we found it, it was the hood closed switch! We removed it for now and it's back to megaohms. I removed the gauges temporarily so o can't see of this will cause any warnings or backlash yet... Lol

gtroth

47mA is typical. 0mA, which is what you'd get with megohms, is unusual. I suppose I just don't understand what we are talking about here.

lina944

Sorry, I should have specified. I meant mega ohms on that particular cable for the hood switch, which was causing the low resistance before for some reason.

All is good now though!

lina944

Quick update, bought the car and loving every minute!

jr10cross

I had that exact issue 2 months ago @ mytrplseven, the factory alarm system that was located under the dash directly under my lights switch was causing the issue. I remove the alarm system and my drain went away. In case anyone else has this issue definitely check, I concur!

gtroth

Nice!
What's the battery drain current on that baby