Dash goes dead!

I have a 1999 Dodge Ram 1500 pickup with a 5.2 motor. It has developed this intermittent problem where first the ABS and Air Bag warning lights will come on. Then the Low Fuel indicator and the Check Engine light come on and the odometer reads No bus or No bu5. It is hard to read. Finally, all of the instruments go dead. The truck continues to run fine. Then it will go back to normal. I recently replaced the Head Light Dimmer switch but it was a while before the problem arose. We have changed the Speed Sensor on the rear differential but that did nothing. Help!