2001 VW Golf TDI engine oil pressure light

I have a 2001 Golf TDI automatic. Since this past winter the engine oil pressure light has gone of intermitenlty and very sporadically. I do notice that it will go off above 3600 RPM and only goes off above 1500 RPM. I have taken the car in twice to have work done at a VW dealer and they cannot replicate the light. I regularly check my oil and it is fine. I also just had the glow plugs changed and the timing belt replaced. The car is nearing 90 K. I am trying to sell the car and would hate to have this problem when i sale it.
Does anyone have a solution to this problem? My solution is to have the light dismantled, but can't seem to figure out what fuse it is. Any help would be great!

Are you using a VW oem oil filter?
i've never seen oil lights come on on 1.9tdi but it woulds like you may have a faulty oil pressure switch.