SinceI purchased my blazer the heat when set to the floor will blow out the vents when going up an incline. As soon as the road levels out it will switch back to my feet.

It is not a huge deal but I figure if someone knows what it is and it is cheap I will fix it. What do you think?

 

Could be a loose connector that moves based on the cars position, or something else.
You say it changes when the car is on an incline, wich leads me to think a loose connector, but you dont explain exactly what on an incline means. Sometimes, while driving uphill the engine speed changes to keep the car going. This opens the throttle, reducing the available vacuum at the engine.

The actuator which closes the vents requires a good solid vacuum, so if the vacuum drops off, it may open. On mine, it takes a few seconds to actuate, while the rest of the positions have no problem. In fact, most of the positions will operate with the car off, but not the vents. The car has to be running to pull enough vacuum for the vents to shut off. I would gather more data and see if you need to start looking for a vacuum leak.

 

Anytime I drive up any sort of hill, whether the rpm's change or they stay at the some position the air will start blowing out the vents. Speed does not seem to have any effect on the issue.

I also have a delay when switching between floor and vents and viceversausing the turn dial. I would say a good 5 second delay.

 

Engine vacuum. Your problem is an insufficient supply of engine vacuum to the HVAC system. This could be a result of a cracked or collapsed vacuum line. Could also be a result of transmission fluid in the vacuum lines from a faulty transfer case input seal and/or vacuum switch on the t-case.

This happens because, regardless of your speed or engine RPM, when you go up a hill, you press down on the accelerator to keep speed constant. As a result, engine intake vacuum drops. An insufficient supply of vacuum pressure to your HVAC system will cause the symptoms you are experiencing.

 

Is there a common spot for this failure that I can look at. I am not familiar with the location of these lines at all and was unable to locate a diagram. Any help would be appreciated.