Oil Pressure question-

[lip277]

Hey folks-
I noticed the oil pressure gage in my W126 420SEL is pegged all the time (at 3 bar). IT happens even with the car not running but the power on. It just happened recently.

Question....
What are the voltages I should expect out of a working gage...??? I'm going to do some looking at the car and want to know what to expect. Would an open circuit (broken wire or infinite resistance) give the pegged reading or would that give 0 pressure? I figure it's either one of those that would do that (open or closed circuit). I figure I need a new sending unit but want to at least try to verify it before I get one.

Thanks