I recently purchased a 2001 Chevy Tahoe LT for a hunting truck. When I test drove it, the air and heat worked great. The next few times driving I noticed the air was not blowing cold. I changed air controls and never could get it to blow cold. I was driving the other day and after about 45 minutes the air started to blow ice cold! It lasted about 15 minutes and it was back to warm air. It has randomly kicked on like 3 times since I’ve owned it, but I’m not doing anything special and I’m not going the same speed each time when the air starts working. Has anyone else had this problem or any mechanics out there know what my problem could be? Thanks in advance