Heat constantly blows out floor vents

[hntr45]

Hey guys, so I have been having issues with my HVAC. woohoo.... anyways I know the problem must be vacuum related but I can't seem to figure out what is actually wrong. I would assume that the vacuum reservoir under the hood is fine because i do get vacuum into the firewall. From there it goes into the vacuum selector switch (controls ac, floor, vent, defrost, etc.) after that I have no clue what to check. I recently replaced the vacuum selector switch also, but it did not fix it. I also noticed the motor directly behind the glove box is not opening when it should. I pulled the white hose off of it and checked the vacuum, and there is very little vacuum. I'm not sure if that helps at all, but I want to be specific as possible because I don't have too much experience with vacuum lines.

 

[adsm08]

It's possible the line is pinched or plugged.

 

[Mark_88]

From what I recall (and there was recently a good article on replacing the A/C but also covered how things work) the blend door on the right by the kick panel opens and closes when the engine is started/turned off. If you have no vacuum there you need to trace the line back to the selector switch and make sure it is connected there.

I know it's pretty cut and dried as to how they connect, but it's also very easy to actually not connect them properly...as I've done so myself.

Once you've confirmed that there are no leaks there (and the vacuum is critical to engine performance) it may be necessary to start checking individual lines...but...

You said there is vacuum to the firewall...how far did you actually test that?

Aside from confirming that...the only other thing that I know of that can go wrong with these controls is the blend door...and you will probably hear it thunk (or whatever noise it makes) when it is changing air flow...the blend door can, apparently, break and stop functioning...leaving you without certain functions...usually no heat at all or no A/C

You can use the search function at the top right to search for specific items...or check out the Tech Library for more complete troubleshooting information...if nobody else provides a link, that is!

 

[hntr45]

That could be true.. on my ranger I believe the blend door is electronic. And i have fixed it before but it is possible that it broke again