[s-cars] Electrical draw/weirdness after shutdown

[Graydon D. Stuckey]

Hi guys,

I hope someone has diagnosed this problem before.  I am confident that I
will find this gremlin but I am not too proud to ask for help.  :-)
Actually, my pride is tired of crawling around under my car.  My car ('92
S4) has a residual draw after shutoff that can drain the battery in a couple
days.  I have placed a current shunt into the negative battery cable that is
rated for 100 amps, and I am monitoring the current draw with my voltmeter.
I've tracked down a few other unrelated(?) electrical issues and fixed them,
but this one last major one still eludes me.

Right now, the car is not drawing an unreasonable current draw and it
appears to be working properly, however, only an hour ago it acted
strangely, drawing over 50 amps for a few moments.

When it draws, the power window control module clicks on and off.  When on,
it draws current, and when off, it seems to drop down close to zero.  Then
if you touch the door lock switch, it will stop.  Oddly enough the door lock
switch is one thing that still doesn't respond.  The key works with the IR
sensors, and the alarm sets itself but if I try to lock or unlock the doors
from the door lock switch, nothing happens.  Now that I have typed this, I
wonder if a previous troubleshooter has moved the wire from that door lock
switch to something in the power window circuit by mistake.  I need to trace
that a little more carefully.

I did remove the power door lock, interior lights and IR remote module which
includes the vacuum motor, beside the battery.  I took the two PCBs apart,
and checked every diode.  I took one enclosed relay off, and checked it out.
The other relays I cleaned with contact cleaner, and I changed a 100uF
capacitor just in case it was getting leaky.  Then I resoldered the boards
back together.  I don't think it helped any though.

I might do the same next with my power window module.

Any ideas?  Thanks in advance.

Later,
Graydon D. Stuckey
http://elektro.cmhnet.org/~graydon/