2000 C230K PSE pump/parasitic drain relationship?
 

In trying to track down a .27A draw on our new battery, I pulled the white connector on the PSE (Control Line, according to AllData diagram) and the draw immediately dropped to an acceptable .02A. Before I dig into it (and possibly ruin the damn thing), is there anything else I should be looking for?

Incidentally, the parasitic draw acted oddly, with the ammeter (set at 10A, hooked in series, after shunting) fluctuating between .27A, then .04A, then .08A and back to .27A.

Also, we were having (sporadic) difficulty with the driver's window going up.

Do you think I'm on the right track, thinking it's the PSE? If so, what should I look for when I'm inside it?

THANK YOU!

I would have to know a bit more about your testing technique, but if you are interested in some reading material you might check these:

http://www.continentalimports.com/ser_ic030538.html

http://www.mercedestechstore.com/pdfs/507%20Systems%20I/507%20HO%20CAN%20B%20(ICC)%2010-28-02.pdf