Looking for verification in some items associated with my 3.5L OM603. I'm a 616/617 guy, so this is my first experience with this engine. Ive read a lot of threads, but want to verify my proficiency.
These are the temperature sensors on the metal housing that connects to the upper radiator hose. For some model years, one is for the temp gauge needle, another is for a low/hi aux fan engagement. However, some theories are that in the later models, the temp sensor for the aux fan is in the head behind the IP, and that the other sensor (blue?) is for the electric diesel system, Klima, and/or other idle controls.
This is the other temperature sensor, mentioned above, that's in the head. This one is for the aux fan??
This is the electric diesel control connector that somehow adjusts idle and affects the IP:
There's also this electrical connector in the IP. Not entirely sure why...
There's supposed to be a variable resistor of some sort by the brake booster, that can be set to affect idle speed. My car does not have one. Just this silver box with the fuse in it. Not sure what that's for - ideas??
This red sensor is the overpressure switch for the aux fan. Removal of the red switch will cause refrigerant loss. However, a standard blade fuse as a jumper between the two white electrical connections should force the aux fan on??
I don't believe my aux fans are working, causing a slight temperature creep in slow traffic. The fuse looks good, though the metal strip is a bit soft. I guess I need to check the relay as well, but jumpering is easy. I'd like to verify that both switches work, and depending upon the color of fan switch in the coolant path, change to a more conservative setting.
Thanks!!