PWD 87 Carrera Coupe

I detected a draw on my battery using a Fluke meter that was caused by my power seat / air conditioning fuse. After removing the fuse, the draw on the battery (approx. 2.86 amps) stopped or reduced to an acceptable level, a reading of approx. .06 which I believe is only the clock. I believe the draw problem is caused by an open seat circuit that I caused by removing the driver side vertical fore and aft seat switch (e.g. the switch that controls the vertical part of seat moving back and forth) and moving it to the passenger seat, which needed the switch. I have the new switch and have been meaning to put it back into the driver's seat but haven't done it yet.

Can an open circuit cause this sort of draw on the battery? Or do I have other related power seat problems that I have not yet detected? Any suggestions on what to check under the seat if the open circuit is not the problem?

Thanks. Pat

87slant-nose-cabriolet

pat,
an open circuit is by definition an incomplete current path so how could it have
an amperage draw? if the switch is slightly
sticking it could be discharging trough the seat motor.check for a hot motor that is frozen up or binding

Paul H

You have one of two things a) a 'short' to ground (highly unlikely given the low current) or b) a constant 'load' that should not be there. You need to use your ammeter and unplug things in the seat & AC circuit until you find the culprit. Use your cars wiring diagram to check everything supplied by that fuse. You're using 35 watts, something is warm somewhere...

George 86T

Pat--what did you do with the switch wires when you disconnected them? They should be taped off until you reinstall the new switch. Letting them dangle could cause any kind of wierd condition if they're touching some poor ground. Make sure you have the AC switches all shut down when you attach the Fluke--to eliminate any backcircuit potential. As Paul
said something is 'warm' in there.

RoninLB

Long shot, to much of a coincidence[sic], but a bad solnoid could cause el. drain problems.........Ron

Adrian

Dear Pat,
Firstly the facts. As already has been stated, an open circuit cannot cause a battery drain. To have current you must have a circuit.
A live wire with 12VDC on it that touches ground will not only spark it will blow the fuse.
What you have is a resistive circuit to ground. I doubt it is actually in your seat circuit but it should be repaired first to make sure.
Do not discount the aircon system circuit. There are some really nice things here which can cause such a current draw.
They include,
Compressor clutch caused by welded contacts on the control relay for the clutch.
The speed control resistors for the fans.
Now a very important question. Do you have this current drain with the Ignition ON or OFF. If OFF then you need to be looking at how wired direct to battery circuits. If ON, well then it is a little bit more difficult.
I had a similar problem on my 964. However it was the Radio Booster drawing 2amps.
I do have some 3.2 Carrera drawing at home and I will see if I can see anything but please tell me if Ignition is on or off. I assume off. I also need a better description of this fuse. Rating of the fuse etc. I find it strange that aircon and seats should be hotwired.
Ciao,
Adrian
911C4