Oil Pressure Gauge - pegged when ignition 'ON' and engine is off - 95 E320

[71Rcode]

Hi all. I've been on this board for several weeks doing tons of research before I bought my '95 E320 (75k) a week ago. My first MB (former volvo guy) - and I love it.

I'm a DIYer, totally. Just yesterday I replaced the front brake rotors/pads / valve cover gasket. Great posts on this board helped me with each task - thank you very much.

For my question - I'm a bit worried about my oil pressure, as I just discovered my oil pressure gauge peggs (number "3" on the gauge) when my ignition is on, and the car is not running. And when the car is running, the gauge still pegs. I did read somewhere that this could be a faulty oil pressure sender or wiring issue, OR....something shady could've been done to mask low oil pressure - like wire the gauge to where it pegs when the ignition is on.

Can you guys please advise me on where this oil pressure sending unit is? And what steps I can take to figure this out? I appreciate it so much.

Best regards,

71Rcode
Dallas, Texas