Heat won't work all of a sudden on my 96 impreza outback. It was fairly warm last week so I turned my a/c on by turning the temp dial from red to blue and then the other dial from heat to a/c. Then it got cold again and when I went to turn my heat back on by switching it back over to red and putting it on heat then turning the blower on it just blew out cool air. Can anyone tell me why my heat would work fine with no problems in the past then after switching it to a/c for one day it stops working? How do I start to try and resolve this? I need heat!

Edited March 18, 201511 yr by cascadeclimbn

cascadeclimbn,

 

You aren't going to get a response until you can tell us what year and model you have, whether its a manual or automatic HVAC system, and the mileage of the car. There could be a thousand different reasons, but we can't narrow it down to a probable cause until you give us somewhere to start.

Oh Ya I guess that would be helpful. I forgot. It's a 96 impreza outback. Don't know the difference between the HVAC systems. 250k on it

Edited March 18, 201511 yr by cascadeclimbn

Most likely the cable that goes to the temp door is no longer hooked to the flapper door or the dial on the panel  The tab that connects the dial to the push pull cable breaks pretty easy.  

Most likely the cable that goes to the temp door is no longer hooked to the flapper door or the dial on the panel The tab that connects the dial to the push pull cable breaks pretty easy.

How do I check that out?

cascadeclimbn,

 

(Told you ... once we knew what you had!)

 

Generally you have to pry off the surround trim from around the air vents/radio/HVAC. Most models just require taping a flat blade screw driver (to keep from marking the trim pieces) and prying the surround trim off. If its different than this, hopefully someone will jump in with the procedure, but it most likely is as OBW's are this way.

 

Then you'll see that the HVAC switches assembly is held in place by by 4 screws. Remove them and pull the unit out of the dash as far as it will allow. Then follow the cable back to the heater box to locate the problem.

 

Because I don't have any experience with Imprezza's, someone else will have to be more specific. Good Luck!

Edited March 18, 201511 yr by gbhrps

Ok so turns out the plastic clip on the dial that pushes a metal pin in and out was in fact broken off. I temporarily resolved this by just manually pushing the metal pin (is the cable you guys re referring to?) all the way in. Started the car up and the heat started blowing right away. The weird thing though, and the problem im facing now, is that the heat will only work intermittently. It's been blowing cold and hot for the last 2 days. Any ideas why this would be happening in conjunction (or perhaps totally unrelated)  to the plastic clip being broken?

How's your coolant level?

yeah you need to make sure your coolant levels are topped off and no air bubbles in it.

 

If it still doesn't work after that, then make sure the flap door is working properly.

 

if that is working properly and the coolant levels are high,, then you might have some kind of obstruction in your heater core.

 

but chances are 99% its either coolant level or flap door.