Any clues to why 4x4 dash lights blink?

I have a 96 Ford Explorer. Sometimes at start, the 4 wheel hi and lo lights will blink 6 times. When that happens power windows do not work, nor will engage in 4 wheel drive. It is intermittent, it might last 2 seconds, or a month. It may happen at any moment. I have checked all fuses, all ok. Does not affect drive performance. Any logical suggestions would be appreciated.