Any sporadic operation of the rear windows?

My 89 190e 2.6 had similar problems with window fuses. Turns out the wires that go from the b pillar into the rear doors were severed (this is a common problem with w201 chassis with power windows) and were shorting even when the windows were not being used.

I ended up removing the rubber wire conduit, and found that the wires were completely severed on BOTH rear windows. This was surprising to me because the PO was a family member that very rarely used the rear doors. I soldered the wires and fitted heat shrink tubing. Now all windows work well, and no more blown fuses!