Darwantae951

Hey guys, just joined up today. Took delivery of a 1988 951 S last week and I'm experiencing a problem with it. It has an aftermarket MTX 200W amp and one 10" MTX sub in the rear, which I think might be the problem, but I have a power drain and I cant seem to pinpoint it. I heard my freshair blower was still on after I removed the key so I pulled the fuse and let her sit for a while, but still there is a drain. The amp turns off with the head unit, so I dont believe that this is the problem. I'm not too familiar with electrical systems, anything mechanical I can handle, but this leaves me in the dust. Has anyone else had this type of problem? Any help would be greatly appreciated. Thanks a lot.

-Darwin

Matt H

Are you sure it was your fresh air blower that was still running and not the cooling fans? The fans are designed to run after the car is shut off.
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Chris_924s

Check your main chassis grounds, power - and supplemental power and grounds. make sure your alternaor is putting out the correct readings.

Welcome to Rennlist!

AznDrgn

An easy way to narrow down the circuit that is draining your battery is to remove the positive battery cable and put a multimeter in the line between the cable and battery and set it to read DC amperage. Normally it'll be a really small number which is just what the memory in your clock and stereo need. Anyways you'll come up with an amperage reading and then one by one start pulling fuses and look for the reading to drop. Do this to all the fuses and you should find the culprit circuit and you can start narrowing things down from there.

Darwantae951

Thanks guys, glad to be a part of Rennlist. Thank you for the help, now all I have to do is find a multimeter...which shouldn't be too hard. Thanks again, I'll tell ya'll how it goes.

-Darwin

pete944

AznDrgn said exactly what I was going to say.
Do that and you'll find your problem.

Chris_924s

I agree, a much better answer.- an excellent place to begin diagnosis.

lleroyb

Azndrgn is right on the money. I can't help but think your aftermarket amp is the problem though. If Azndrgn's method does not stop the drain, I would disconnect the amp. For that much power soweone might have tapped in ahead of the fuse panel. Hopefully if that is the case, they used an in line fuse.

BTW never run an unfused +12v lead, I almost lost my one year old Scout that way.

Lou

944Fest (aka Dan P)

A common power drain is the driver's door switch. If that switch is sticking, the car thinks you are still in it after you remove the key, and some systems stay powered up like the power windows. Pay attention to your dome light. Is it working normally when you open the door to get out? Try shutting the ignition off and opening the door, THEN activate your power window. If the window still works, you've got a stuck door switch, it is in the jamb. Remove it and clean it up may just do the trick.

Congrats on your fine taste in cars!

Darwantae951

Hey guys, have some progress. Hooked up a multimeter and discovered that a fuse was still in my fusebox that was for the heated seat option, and I have no heated seats...It was registering a pretty sizable drain on the battery, and since its been removed, the battery has stayed at a constant level. I will check the amp wiring...it seems to have been installed in a fairly cheap way, I took pics with a digital camera today, can anyone help me on how to post them? The car started right up after sitting for 2.5 hours, so things are looking better. Thanks again for the help, Ya'll have already done a lot on this one thing!

-Darwin

KuHL 951

Sounds like one of the OEM seat heating wires under your seat might be bare or shorting out. If pulling the fuse helped you've found your culprit. Are your seats original? I would still check for that bare wire though, could be that adjacent wires will go next. Maybe they are pinched in the seat track.

AznDrgn

if the wires are bare and shorting out they should blow the fuse almost instantly but there is always a possibility.

KuHL 951

I had a high resistance contact in my parking brake circuit drawing over 1.2 amps and it never blew a fuse or made the light come on. The contact on the switch plate had bent and was slightly touching the mounting frame. You are right though, it will usually blow a fuse.

Darwantae951

Oh and thanks for telling me about the drivers door switch, mine sticks, but it doenst cause the light to come on....not sure why ::shrug:: I plan on getting a new one from GPR or Performance Products. If anyone has an extra lying around and wants to get rid of it, send me a PM. Thanks again guys!

-Darwin

944Fest (aka Dan P)

If the light does NOT come on, that is a bad thing, and very well could be a part of the problem. Remember, when the light comes ON, that means the car recognizes that YOU are exiting, and it can discontinue to power the items it leaves powered up while it still thinks you are in the car. (windows, etc..) This is the opposite of what you'd expect, for example... "My dome light stays ON when I get out and drains the battery". If your dome light stays OFF it will drain the bat in a 944. Remove the switch, soak it in WD-40, exercise it a hundred times, put it back. Case closed. THEN change the sig.. Next pay check, buy a membership. It has already paid for itself!!