Oil pressure sender location
 

Where is the oil pressure sender on my '85 500SEL? Is it next to the oil filter?

I am not positive on the 500sel but, on my 300e its behind the oil filter between the engine and the firewall. The oil pressure sender is easily accessable when the oil filter is removed and the hood is in its upright position.
Good luck!
Adam

Should be roughly the same location as the 560, on the leading edge of the filter housing. Look between the filter housing and the air pump, takes a 17mm wrench to loosen.