I have a 2000 Blazer, my heater switch all of the sudden quit blowing on the floor setting, if you put it on the floor select it just blows out the defrost vent, nothing out of the floor vent. I was thinking maybe control switch, not sure though. Any help would be greatly appreciated, Thanks. I almost forgot to add, I smell anti-freeze off and on inside the truck with the heat on. Not all the time. I suspect heater core for that.

 

First-off:yup core job coming! Not too familiar w/ '00 control system,but so much has been posted on this issue:search this site,you will find your answer! Let us know...

 

I have checked all the vacuum hoses under hood for leaks, found none. I hear no vacuum leaking inside from under the dash. The thing is I dont want to just start throwing parts at it, I am sure someone has had this problem before.

 

I had the same problem on my 95 Blazer, the PCV valve was bad. My mechanic claims the vents get the vacuum source from the PCV valve and if it goes bad anything else vacuum operated will not work...

 

My 2002 Blazer with the manual climate control is at the dealer now for the floor heat problem. Everything HVAC related worked except no air would come from the floor vents, it defaulted to the defrost outlets in that setting. They called me yesterday and said one of the heater box doors was broken inside the box. They ordered the part and it should be ready later today or tomorrow. Will post back with cost and part number. Very sure it will be an expensive fix.

Oliver

 

Got my Blazer back and the floor heat is now working. The service tech had to remove the dash and partially dissasemble the HVAC box inside. He replaced:

1 52487574 Lever
1 52470781 Valve (Door)
1 15046436 Grille (Center Top of Dash)

Total amount $555.00 which is a lot less than I was expecting. Now I can keep my feet warm in winter and cool in summer. The door was broken at the shaft that exits the box where it connects to the actuator rod and spring. It broke one morning when it was ~20 degrees outside. Our Dealer has always been great since we bought the vehicle. Over the past few years, it has had a new intake manifold gasket, new radiator and the driver side door hinge pin bushings repaced.