Ron,

With regard to installing a new sensor I posted the procedure and precautions some time ago, but that post is probably no longer available through the search process. Unfortunately, I didn’t keep a copy and I don’t know whether it’s been archived anywhere. Beyond sinking the leads, using the correct temperature, solder and heatshrink tubing, I also recommended that you repack the sensor case with new heatsink grease. This will ensure more even heat transfer between the sensor and the outside world.

When the W124 was introduced and for some time thereafter, the sensor was located in the left-corner bumper absorber. This location always made more sense to me than behind the license plate. Seems to me that the center location would be more prone to false readings particularly in city traffic, due to proximity to the radiator and exhaust from the car in front. I have no idea why MB moved the sensor back to the license plate location (maybe their engineers know).

Looking forward to the results of your tests,
Barrie