Oil press sender

I have an issue with the oil pressure sending unit in my 92 Dakota w/318 Magnum. Truck has a gauge in the dash and it would seem that the switch or the gauge is bad. I was wondering if I could ohm out the switch or add a potentiometer across the plug and use it to get the gauge to work or verify that it is the problem. The switch is the 2 plug slim type as opposed to the single wire fat one. I've looked for specs for both units, switch and gauge, but have had no luck. HELP!

What has nobody ever checked these out? Or do you just repace things in hopes of correcting the problem? I was wondering what kind of restance readings I should get and if I use a pot across the plug can I mimick the switch?

Better off just buying a new sender or grabbing one from the junkyard. These things die from time to time.

Has the gauge worked before with the switch that is in it? Most gauges require the "bell" switch.

The switch in there is the original equipment one. According to the previous owner the gauge quit working about 8 years ago. I also noted that the temp gauge was acting funny as well. I am looking for comformation that the switch is bad or is it actually the gauge? I'm cheap and refuse to just replace parts in hopes of fixing it.