Oil pressure gauge.

[Doughnuts]

Happy new year every body.

I have been having an issue with my oil pressure gauge in my 91 c1500. The gauge typically sits at 60. Sometimes though it will sit at its correct location but that is only for brief moments. Now I am know that its not actually running with 60+ pounds of oil pressure at idle, so it must be that gauges fault or the sender units fault. So I have been doing some research on the sender unit and it seems there is two of them, one behind the distributor and one above the oil filter. Now from what I've read the one behind the distributor works with the ECU and has noting to do with the gauge, and the one above the oil filter is used only for the gauge. So I climb down under my truck and behold there is none. Now my question is this, How do I get my Stock oil pressure gauge working again? And how do I find out what it is plugged in to.

Thanks.