Wouldn't it be great if there were a search function where you could find a "fuse chart"?

http://www.peachparts.com/shopforum/showthread.php?t=242913&highlight=fuse+chart+300sd&page=2

http://www.peachparts.com/shopforum/showthread.php?t=222658&highlight=300sd+fuse+chart

Fuse 10 appears to be the master fuse for just about everything A/C related and your water pump, so #10 blowing may affect temps.

But the "hop" as you describe it sounds weird. Literally "up and down" and not rocking side to side? A bad idle will cause the car to rock and you'll bounce up and down in your seat.

If it's as bad as you describe, you could be rocking something and shorting one of the things on the #10 fuse. I think someone just described where the kickdown switch on the tranny shorts out due to exposed wires: rocking + exposed wires on the circuit is an easy recipe for popped fuses. Or it could be a bad blower motor.

I'd get an assistant, pop the hood and stand to the side, have the assistant start the car and put it in gear at idle (just like you'd be a stop light) and you should observe what's going on with your belts and compressor. Smooth steady operation or jerky motion?

I'd still think you've got a seizing compressor or slipping belt that makes the engine rock. You may have bad motor mounts and shocks that makes it even worse.