Heater Control Valve
Question? I was looking thru the parts catalogue and they are showing a part called a Heater Control Valve for 69-72. I'm building a 71 RS and I don't see anything in the factory assembly manual that references this part or it's presence. I understand the concept is a vacume controlled valve that stops the flow of water to the heater core when the control is not in the heat position. I believe my control just uses a damper door that blocks the heater core radiator.
Does anyone use this or know of the need or negaton of this part or am I complicating a simple thing? The reason I bring this question up is that I have three vacume lines coming from the AC vacume controls out to the engine compartment. I know 1 goes to vacum, and 1 goes to the purge door actuator but i'm stumped by the purpose of this thrid line and thought maybe that was what is was for but my instinct tells me I'm wrong since the damper door is cable controlled. Any input on either of these items from anyone
1. Use (or need) for the "Heater Control Valve"
2. Location and use for the 3rd vacume line from AC control grommet.