I recently bought my first truck. It is a 2003 Int'l 4300 straight truck with a Dt466, air brakes and suspension. I have a few questions about it. First there is no switch inside the cab that I see for dumping the air in the air springs. How do I do that? Secondly, I see that I have two fault codes that display on the dash. How do I figure out what they indicate? Third, and finally, being in Minnesota I have to plug it in at night most of the year. Last week it was minus 15 when I went to start it. It didn't start even though the tanks were full and it was plugged in. How/where do I check to make sure the heater(s) are working? Is it a block heater or ?