Tire Pressure Monitoring System problems of the 2007 Toyota Prius

The Prius headlights turn off randomly while driving. Sometimes one, sometimes both. There is no pattern and they go back on when the on/off switch is activated. This has been going on since about 40,000 miles. The bulbs were removed and reset and the right side was fixed, the left side fails less frequently. This is a potentially dangerous situation since the dealer does not seem to be sure of the cause of this problem. The cost to replace the bulbs is over $400. There is no guarantee that this will fix the problem. The tires wear out very quickly; replaced original tires at 22,209 miles and now at 50,287 miles the second set has to be replaced. The tire pressure light goes on continuously, regardless of pressure.