When I 1st got my Blazer almost a year ago, the vents worked fine....then all of a sudden they just stopped. No air whatsoever comes out of anything except the defrost and a little out of the floor vent. A friend said the entire dash would have to be taken off and the hoses checked to see if they have come loose....does that sound about right or is there an easier solution?

 

Several possibilities but the ones that come to mind are the fan motor or fan motor switch being dead or the blend door being stuck in some weird position. I figure a good portion if not all of the dash would have to come out if these were the case, except for the switch which is quite easy to remove.

 

check the vaccum lines. could be a broken line preventing the door to switchto the vents and stuff. can you hear the fan motor blowing at different speeds if you move the fan switch? also whats the year of the truck?

 

The fan still blows out of the defrost vent and some on the floor...and yes, I can hear it change when I switch speeds....it's a 1997

 

There is a ball-shaped plastic container under the driver's side rear of the hood (it is bolted to the hood itself) check to see if the vacuum hose has come off of it, if so just hook it back up to the port hole and start the engine...let it idle for a few minutes to build up a vacuum in the tank and it should fix it. If it isn't off of the tank, then check for any rotted vacuum hoses/connections under the hood first. Then check to see if you hear a very faint hissing in the dash with the engine running, put your ear next to the heater/ac control head (the fan/mode switches) and listen for the leak. If you hear a hiss sound...then your rotary vacuum valve (on the back of the mode selector switch) is leaking. Let me know what you find please.

 

Thanks a bunch...I can't check it out right now cause my Blazer is in the shop....I have another post all about that issue if u wanna check it out lol...but as soon as I can get it back I'll look and see what I find

 

Mine hissed for a while before the vents quit working(the hiss went away).

 

I checked the ball-shaped plastic container & it looked like everything was where it should be, although I don't know a whole lot about things under the hood. I didn't see any hoses that looked rotten or hear any hissing, which I guess if I'm like DetroitMuscle, the hissing came before my vents went out lol

 

The hissing came from the heater control switch thing, unit or box wtfever they call em. You really wont hear any hissing unless its a big leak, check your vacuum lines, they are small and black, see if they are cracked or crumbly, they are usually 5/32 in size and 7/32 in size, kinda like the washer fluid lines. Mine is a 92, but just the defrost and floor working is enough to keep my sweating in the winter.



By the way, if you were anything like me then I wouldnt be Me. its a vicious circle, sorry lol.

 

No, those were the lines I looked at & they seemed fine....the defrost & floor vents working is good enough, I just can't stand to have something not working....like my back windshield wiper needs a new motor and that annoys me lol but I can't afford to do anything to it right now so I'll have to deal with it lol