On my '97 F250 the gauges all seem to give strange readings after the vehicle warms up. When its started cold the Battery and Oil Pressure both read about mid level. Then after about 5min the truck gets warm and the Heat gauge shoots to the top, the oil pressure goes to zero, and the battery shows max voltage.

It did this when I first got the truck then the alternator died and I replaced it. The previous owner said the gauges worked fine until he replaced the alternator on the truck 2 years ago. I'm a little bit worried now since the truck has burnt out an alternator within 2 years.

My question is do you think there is a related issue between the gauges and the alternator or would you say they are separate issues and the alternator that burned out was just a dud from the start?