No heater, AC blows instead... :(

[killj0y]

Ok so first signs of cold down here and my heater isn't working damn! It was fine a month ago when I accidentally turned it on. Just wondering where to start troubleshooting

When I turn it on it feels like actual ac versus just no hot air. It even has the exterior condensation as if I had the ac on. Anyways any help is appreciated!

 

[killj0y]

My bad can a mod move this to heating and AC?

 

[LearjetMinako]

A few things to check
1. Coolant level, make sure the coolant is filled
2. Heater blend door actuator, check to see if it is actually working and not blocked.
3. Heater control valve, make sure this valve is working. It is located in the engine bay, in-line with the heater core hoses. There is a vacuum line that operates it.

 

[straycat]

Check that thermostat, Bro. Make sure your control knob switch is actually working as well when you set it for the heater.

 

[killj0y]

I replaced the heater control valve but it only blows hot at highway speeds. The tiny vacuum connections broke at the connector, replaced it though. Could it not be making a good seal thus causing a vacuum leak? But then why is the ac blowing? Hmm...

 

[martin]

When the air is directed at the windshield the a/c runs by default (it de-humidifies the air)

 

[superds]

My guess would be a bad vacuum line going to the dash controls. I went through a similar issue with my 99 explorer. I could only get air to go to the dash since that is the default when there is no vacuum present on that line. And like Martin said, a/c turns on when the blender is directed to the windshield.

 

[killj0y]

Ok glued the vacuum connector to the tube and send to be working now. But my ranger send to be needing a fair amount of water. Checked the oil and nothing. Can't find a leak anywhere. No smoke out of the tail pipe either. Originally I thought it was the heater core burping cuz it spilled all the coolant when the control valve went. I've put probably a gallon in three times in since I started this thread. Again no signs of leaks and no water in the oil/combustion chamber that I can see. Otherwise the truck is running great. any ideas?

 

[killj0y]

Bump

 

[snake]

Pressure test this when cold, often times a cold water leak is more common than a warm one. If u don't have a tester but own a compressor, turn it down to 20 lbs or less and use the redneck rad test- with the rad cap on, blow compressed air through the coolant recovery tank line toward the radiator. The pressure will slip past the rad cap and hold if it is working correctly. Let us know what you find.