Originally Posted by joe21511
My 98 is having similar problems it will randomly switch defrost an vents an then when you let off the gas it goes back to eat it's set on
joe that is defiantly a van leak, the fact that it changes when you give it gas or not. the vacuum gauges you buy on the after market do the same thing as the motor runs it pulls vacuum when you let off it gives more.
my 56 chevy had vacuum wipers, you think the heat thing sux! lol try driving in a down pour with no wipers lol