My 96 Jetta 2.0 has its temp light blinking, but only when its cold out. What triggers this light?

The low coolant sensor.

My 94 jettas oil light will blink and beep at least once when i drive it. I checked the oil level and its fine. what could it be.

If you haven't heard any noises like lifters rattling then suspect a bad oil pressure sensor. There are two and they are different from each other. One on the cylinder head and another on the oil filter housing.