This may seem silly, but I can't get the integrity sensor removed from the wire harness on my 1991 240. Is there something I'm missing here? I have it loose, and can grab both sides reaching under dash, but can't get them separated. Concerned I'm gonna break something if I pull too hard. I can't find a notch or anything like that holding them together.

 

there may be a plastic tab sticking through the middle of the socket which you have to press sideways to release it. I see that in some pictures of the replacement relays but not others, notably here, http://www.davebarton.com/pdf/bulbfailure86-93.pdf (which shows the guts of the 'red' bulb relay, and how to gut and bypass it).

i'd unclip it from under the dash so its hanging down on its harness, then use a small flat screwdriver to lever the plug off, a little at a time going all the way around while holding that lever if there is one.. dribbling a bit of DeOxit into each pin from the back might help loosen them.

 

Thanks! Got it off finally. Yes, the existing sensor has a tab inside that you have to push toward the center, the replacement has no such tab.