I don't know why but it seems that most manufacturers like to install the radios near the heater/ac ducts. In my Jeep Cherokee when I run the heater it causes my N4 to heat up really bad and it stops reading dvd's. The installation manual says to avoid heat sources but what option do I have, really? I put some muffler heat tape between the radio and the duct but it's metal side towards the radio. I think if I turn it around it'll help a little. I've also blocked off one of the other ducts and installed fans in it to exhaust the radio compartment. It dissipates some of the heat but I think I'm going to put another fan in the compartment to blow across the radio towards the other exhaust fans. Has anyone else had this issue and resolved it?