2003 Sunfire electrical problem

Here is my problem I have a 2003 pontiac sunfire, The dash lights are not working. In the beginning the would go out but when I hit the rear window defrost they would come back on, now neither one works. But I did notice something, and I have tested my theory a few time and it always seems to work, I start the car drive for a bit then park it and leave it running for about 20 minutes if I shut the car off and then restart it the lights come on. It sounds like something is pulling apart in the cold or someone else mention that there could be ice interfering with the connection and when it melts (after running for long periods of time) the ice melts and the connection is restored. Is the something that is plausible? It is dark here during the winter for most of the day, and no dash lights is not fun!