If the AC is on Vent and it blows hot air in and the temp is at coolest. I think it does not matter because when you have it in vent it is venting air from the out side, it will start blowing air from the out side meaning if its hot out side the air will come out hot. Sometimes a car might blow hot air when you have it on full AC and cooldest. When you accelerate your car hard but it should cool down after you stop accelerating hard.
Your climate control in your 1998 Ford E250 Cargo Van blows cold air when in heat position and sometimes it blows warm air when in the cold position?
The control of vents on the Third Generation Camaro's is done with vaccum rather than via cable or electrical means. The problem is being caused by a vaccum leak either at the control unit or somewhere along the vaccum source line. Best check for leaks on both side of the firewall. Also, the control unit may need to be replaced. My Camaro had the exact same problem and it was a vacuum hose leak.
The heater control valve is bad. Sometimes the dual heater control valve will go and the AC will blow full heat.
control fuse blows when you plug thermostat to base controlling a gas pack unit
2 thing's ambient temperature sensor malfunctioning if you have computer controlled a/c or heater a/c blend control actuator. I've seen both problems.
VENT TO HEATER CORE IS NOT CLOSING................
Which fuse is blowing - please be more specific as there are more than one fuse controlling many aspects of the car's electrical systems.
In a 1999 Chevrolet S-10 Blazer, the Truck Body control fuse typically operates various electrical components associated with the vehicle's body functions. This can include the power windows, door locks, interior lights, and sometimes the dashboard lights. If this fuse blows, you may experience failures in these systems, affecting overall convenience and functionality. Always refer to the vehicle’s owner manual for specific details and fuse locations.
most likely cause is a bad ground or a short circuit, probably in the radio
You either have a bad controller or a bad actuator.........
Check coolant level Perhaps thermostat is not opening to allow coolant to circulate through engine and heater core
If your 03 Trailblazer blows heat out of the back vents when set on AC sometimes, it could be because of a faulty blower motor resistor block.