I've been having issues with my aux fan not comming on when the a/c is engaged. Well I found the source of the problem today, the fuse box. While metering out the relays, I found that terminal 86 did not have any ground. When I opened the fuse box up, I found the ground circuit to be open. Apparently the PO decided to clip onto an existing hot lead in the fuse box and with various girations in the car, it rubbed against the circuit board and fried the ground connection.
Just thought I would post this out for future 6ers having aux fan problems.