No heater tap. I can still adjust temp. How?

[gemini]

OK I must be missing something. My heater tap snapped the other day so I replaced it with a random heater tap off a ford or something. I blocked off the little vacuum line as this thing doesn't have a spot for it. it just has a lever (which doesn't seem to do anything so I'm assuming it's acting as a straight through pipe) I'm still able to control the temp through the dial, and even use my AC.

How is this possible?? I thought the heater control controls the tap via the little vac line? Im confused...

 

[DavesSV6Tonner]

I suspect the temperature control knob primarily controls the mix of air flowing through and/or bypassing the heater core depending upon the required air temperature. It would seem that the temperature control knob also activates an on/off vacuum switch that opens and closes the heater tap.

 

[gemini]

Yeah I think you're right because when I put the fan on minus the AC and put the temp on cold, I can still feel a slight warmth coming through but with a working tap, the knob will only open up the tap in the red part. Doesn't really bother me, but I bought a new tap anyway. Trying not to do too much dodgy stuff on this car lol.