Heaters

[cam76034]

I'm guessing that the heater system in cars are pretty much the same. So what would make a heater blow semi-warm air, never really hot, but then suddenly go cold?
I haven't checked the thermostat yet.

This is in a 2000 Mustang, and from what I've googled so far, there's a blend door that sounds like it may be the problem.
Anybody else been there, done that?

[sammm]

What's the car's temp gauge read? The heater in my '92 wouldn't get hot and it was the t-stat stuck open.

[black roadster]

My gauge reads right in the middle but I don't think it gets warm enogh either.

[Wes52805]

Does the mustang have electronic climate control or does it use cables to move the blend door? If it's cable operated the chance of it being the blend door is slim. the electronic climate control tends to get stuck and the air never mixes with air in the heater box. Check the T-Stat first! -Wes-

[Radio-Active]

My dad's '95 T-bird had that problem and found the issue to be a vacuum leak. The Automatic climate control sysemt used a vacuum bellows to open and close the blend door and, though the leak was not the bellows, a leaking hose on the engine side of the firewall was all it took to fix.