Hot Vent Air - Blend door problem? 2003 Nissan Fontier



My vents blow warm air, even with the Temp knob all the way down. It is noticably warmer than outside air. The Temp control DOES work, it just won’t block out all heat. I pulled the glove box and ensured the temp cable does push the door to it’s stop. Makes it hard for the AC to do it’s job. Should I rip apart the heater/AC box? I’ve done that on a Dodge and it isn’t fun.


I’m not sure, but most Jap imports don’t use a blend door to by-pass air around the heater core, but use a valve, usually mounted on th firewall to open and close the flow of coolant through the heater core. If the valve corrodes or leaks, the hot coolant from the engine will warm up the air. Check to see if you have an external valve.

Another trick would be to get some heater hose, and by-pass the heater core. Then just re-connect when the weather turns cold. It would be a shame to resort to such a red-neck method on a fairly late model truck, but it is an option.