why does cold air blow out when heater set on hot i replaced the thermostat
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1 Answer
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Autobahn 11/24/2010Cold Air, like AC cold air? I believe this is a blend door problem, its stuck. The blend door is in between located in between the heater core and the A/C evaporator the acutator is outside of it. You won't see or get to it without removing the entire plenum (Which means you have to go under your dashboard). Then have the car running and switch it from heat to cold to see of it opens,if not that could be the problem, usually its the inside control unit that goes bad,that's the whole control unit where you switch from hot to cold or change it from lower to higher vents Look for a cable or vacuum hose attached to the system. If broken or disconnected, this could be your problem. Some HVAC (heating ventilation air condition) systems have an electric motor that adjusts the blend door. This is harder to diagnose as the pivots could have broken stopping it from moving.
