Oil Pressure gauge dead?

[krahe]

After a bit of searching on this site, I am posting asking for help on an oil pressure gauge that reads 0 bar, the needle just sits on the needle rest. From what I have read, if the oil pressure gauge or the sending sensor goes bad, the gauge should read 3 bar.

I've driven the car (89 300CE) over 2k miles, so it's not the case of no oil pressure and the oil appears clean. There is no knocking/grinding/what not and all the other instruments in the cluster appear to be functioning properly, although there is one dash-light out (left hand side that illuminates the oil/fuel/etc. group).

Where is the oil pressure sender and how do I test it? Or would I be better off just replacing it? Is it possible for a DIY test of the oil pressure gauge to isolate the problem?

Thanks in advance,