Like probably half the world's W124 owners come summertime, I'm trying to sort out some warm running condition problems. I went ahead and ordered a fan clutch, which isn't here yet. Along the way, I noticed that the aux fans are not coming on at low speed. While troubleshooting, I noticed that the fuse on the K9/1 relay, which is the blue relay nearest the firewall, had blown.

This is a 1994 E320 sedan, by the way. I'm sorry for having not included that.

Is there a typical situation that causes this fuse to blow? The fan resistor down by the headlight seems to be okay. I tested it with 12V, and it does pass current successfully.

The various forum posts and FSM pages, which I've spent the last three days reading, state that I need to jumper the pressure switch in the AC system. The problem I'm having is that the pictures I see show what I assume to be an early car. The shop manual diagram doesn't look like what I have. I'll post a picture in a second - would anyone mind helping me figure out how to test this pressure switch, and what my next steps are?