Ok. So I bought this 2005 Tahoe & the rear HVAC only blew cold. The dealer gave me a service contract to fix it (which is the only reason I went ahead & bought it). So, they replaced both the mode door & blend door actuators & it worked for about a week. We leave it on heat for the kids, so we never even messed with the thermostat. Yesterday, it went full cold again & WILL NOT move. I also noticed the lights inside the overhead controls for the rear hvac are out. Any thoughts? The dealer says they don't know what it could be & I don't want to spend the couple hundred $ to replace the overhead controls & the control module. Could those be it? Anyone else solve this issue? Thanks & sorry for the long post, Greg.