Nissan Repair: 2004 Nissan Sentra no hot air flow, air flow control, nissan sentra

Question
Hello Calvin,

I have Nissan Sentra 2004, I found several days ago the car cannot create hot air when the Temperature Control Dial indicate on "Hot", no matter where I place the Fan control dial or Air Flow Control Dial.

How can I fix this problem? approximately how much?

Thank you for your answer!

Answer
Hi Frank -

Looks like your air door is either stuck, or you have loss of vaccum to the heater control valve (HCV), or the HCV itself is stuck.

First of all locate the HCV. It should be in the engine compartment along the heater hose in line, probably near the firewall. It should have a vaccum hose connected to it. Turn the engine on, set the heater for the hottest setting. Pull the hose off and check for vacuum. If there is vacuum, then feel the hose on either side of the valve. If one side is hot and the other is cold (engine must be running for a few minutes to check this) with the heater on, then the valve needs replacement.

If the hose is hot on either side, the air door inside the car ductwork is probably stuck. The ductwork is located under the dash, and must be removed to get to that door.

Hope this helps -
aloha
calvin