oil temp guage

The stock oil temp gauge in my center console (74 914 2.0L) has an odd problem...it fogs up when the engine operates. A spot of moisture droplets about the size of a nickel, and not enough water to coalesce and form a drip, forms on the inside of the clear bezel when the engine is run for a short while. The fog only goes away when the engine is shut down, then forms up again within a few miles of driving. It happens every time, regardless of weather or season. I tried to remove the gauge to investigate but the gauge is sealed pretty well by the metal housing, and I didn't take it further. My guess is that the gauge operates on a low voltage signal from the sender and I can't figure out what might be keeping me 'in the fog'.

Any ideas on the cause or cure? Anyone else experiencing a similar condition?

[JP Noonan]

When I got my 75 it had all the gauges and center concole in the rear trunk, it also had about 4-5" of water that had been there long enough to grow a thick layer of slime.

I took the gauges out and removed the light bulbs, spray some compressed air from one of those cans (they sell them at camera shops and comp/mega stores) let the gauge sit face down in an airconditioned room for a day or two. Put the bulb back and reinstall the gauge (if your like me and forget wiring things mark the wires first). I live in Miami and the gauges have been fine for the past 6+ months.