Depending on the year, make and model check the following..............
1. A/C heater control door.
2. Cables and vacuum lines.
3. A/C heater control panel.
Is it blowing cold air only or not blowing any air at all.
Need to know if the blower is working or not or, the air coming out is cold or warm or hot or, the air (hot or cold) is only coming out the defroster.
The heat may be blowing cold air because there could be a problem with the thermostat, a lack of enough coolant in the system, a malfunctioning heater core, or a faulty blend door. It is recommended to have a professional inspect and diagnose the issue for proper repair.
The heater is blowing out cold air only
My 2001 Chevy Blazer was blowing cold air when I had the heat on. My husband flushed the line to the heater core and a bunch of junk came out and now my heat works great. My 2001 Chevy Blazer was blowing cold air when I had the heat on. My husband flushed the line to the heater core and a bunch of junk came out and now my heat works great.
There might be a blend door issue causing you to have cold air, but no hot air. Try moving the lever from cold to hot, and listen for the sound of the door moving.
The little vents (or flaps) inside the heater system are stuck, broken, lost power (they're vacuum motors).
ruud furnace only blows cold air, no heat
There are only heat receptors. "Cold" is a low level of heat.
turn on the car let it run for about 10 min. then pour some anti-freeze in. turn on the heat keep it on for about 5 min. and it should be blowing hot air. Christian Brown
Either you have clogged or busted vent pipe or the actuator could be going bad.
it is blocked and needs to be flushed out