Question please. How can you determine if the time delay unit is working? I have a 68' Coronet 440. Does it make any sound(s)? Is it by function or lack of function that you can determine if the unit is working or not? Or both? Trying to figure out if mine is working. The A/C is not connected but all a/c heater button and vacuum lines, actuators are working. My brown wires (heat) and blue wires ( A/C) are connected. I do know that when HEAT button is pressed, the fresh air door is supposed to open (open to fresh air) yet my fresh air door remains closed to fresh air when the heat button is pressed. All the actuators are connected, vacuum tested and working. So I was guessing that since the time delay is also connected to the rod side of this vacuum actuator, that it's function also has something to do with changing the vacuum and allowing/forcing the fresh air door to into the open position. Anyone tracking with me? Thank you!