I just got an email back from the PO and he reminded me that the rear driver side door window motor is disconnected. It's sitting in the trunk as it needed the $7 plastic sliding jaw replaced and he never got around to it. Could this cause the other windows to not operate?

This is just a thought; I am still going to check the A & B voltages and report back. Just wanted to throw this out there...

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280