Does the car have an after-market audio system? Maybe an amp added?

First thing I would do is look at the positive(+) side of the battery. Is there anything on it other than what looks like a stock positive battery cable? If so, is this add-on an 8/10 gauge wire?

I chased this problem for awhile. Audio shop ran a wire from positive(+) side of battery to the amp in the trunk. Pulled this wire off of the positive(+) side of battery and drain is way down. Unfortunately that killed the radio. I'll get it sorted out when I have time. For now my parasitic drain issue has improved significantly.

My year vehicle was also notorious for the radio antenna causing parasitic drain. Not sure about yours.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"