I could only find an image of the 6000i mixer elbow
and as you can see, it appears to be a threaded plastic fitting which seems kind of odd given that sooner or later that mixer elbow is going to get very hot..... I know of no plastic sender that will stay in place and functional if you have an overheat. It would seem that the sensor speaks to the ECU so yes itís likely that it reads resistance or possibly voltage. Usually these exhaust
temp senders are a simple thermal switch ( northern lights
and Kohler) in contact with the outer shell of the mixer elbow and either open or closed depending on how the protection circuit is wired.
Of some concern is that you have raw water
leaking out of that sender... thatís not good. [ATTACH]