here is where I stand. I too have been having the running-hot problem with my 94 E420. I've been searching around this board and reading about the apparently infamous aux fan issues.
so, my fans weren't turning on. I disconnected the CT sensor and presto, both fans kicked on. Thus my relay is good (..right?). And just for clarification the relay that is involved in this is the dark olive green one that has an integral 30A spade fuse (PN 001 542 9619 if I am not mistaken). In any case it DOES click.
I then proceeded to the dropping resistor. The top terminal was rusted and during the removal process the wire broke. No big deal, I removed the resistor, cleaned up the terminals with a little help from the dremmel, and then crimped a new connector on the wire. Screwed everything back in place and then let the car stand, running. The temp crept up and then BAM! at around 100ish both fans turned on! YES! Thus I can deduce that the CT sensor itself is okay (once again...right?).
Here is whatís happening next. I have full charge on the AC because I just had it refilled (2.2 lbs. of R134 I believe) BUT the AC isnít really cold. I am assuming the other half of the aux fans job is not working. Correct me if I am wrong, but isnít one of the aux fans supposed to turn on to help the AC? What should I check now?
what and where is the high pressure sw [sensor?] and where is the receiver/drier? Which relay controls this circuit?