Heater question

[eric_503]

Before I ripped everything completely apart I figured It maybe easier to ask.

I have a 98 k2500 and the heater blows only abit of warm air. Works on all settings for the blower motor 1-4
But the vents dont change, seems to be stuck on the floor vent. If I leave it off then turn the blower fan on it will be warm for a second then stop and blow luke warm air. (Coolant system was flushed and bled)

The recirculate also works but only on the setting for the vents facing you, not the floor or defrost.
I do have spare blower resistors but I think it maybe beyond that.

 

[east302]

The defrost or any combination of floor/defrost automatically disables recirculate, so that sounds like it is working correctly if any portion of defrost is selected.

It sounds as though the mode damper actuator is not working if it is only blowing out of the floor vent. This actuator controls a damper that diverts air either to the floor or to the dash vents based on a signal received from the a/c control panel on the dash. See diagram below, it's #4.

Look at the actuator and you'll see a notched round thing about the size of a dime. Select full floor or full dash on the hvac panel and watch the actuator to see if the disc rotates.

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EDIT: Rereading your post, are you saying that your temperature isn't blending? Is it stuck on one temperature and not adjusting between full cold and full hot? The temperature door actuator controls that, blending air based on the setpoint of the panel temperature dial.

 

[eric_503]

It's abit of a mix between the two, it's stuck on the floor but the recirculation button works and air flow changes in sound when it's pressed.

And yes I get a small blast of heat then it goes to a Luke warm heat. No matter if it's on cold or hot.