What sort of problem are you trying to fix? The temp sensors don't fail very often, certainly not as often as the much later cars do. The silver temperature regulator box behind the glove box is a common source of erratic temperature regulation (or lack of it entirely).

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]