I've had a problem for a very long time with my 70 Rivi, (Orig manual AC option) There isn't enough vacuum being supplied to move the door actuators...I think? I removed all restrictor etc a long time ago and lost them ou: . That didn't resolve my problem back then either. But now being a little older and wiser I checked all of the selector switches and purchased new one....same problem. Vacuum to the canistor is straight out of the manifold, vacuum from the canistor is strong enough to move the recirc actuator when directly connected (center port). I then hooked the supply to the left (on/off selector) and reperformed the same process, vacuum is suffucient to move the actuator when the switch is swithed to anything but off.. Next I hook the supply to the right hand switch (according to the '70 manual) blocking off the center (temp selector) switch so that there is no source leakage. The result is nothing, no movement on the actuator. So I am a little confused. I have three of the right hand selectors and I put a NOS one in and have the same problem as the original. Am I missing something? The engine does not have a radical cam, there is plenty of vacuum for accessories. I was thinking of direct manifold vacuum to the switched but thought that might be too much for the components. Your thoughts are welcome. Thank you.
Since you did not mention whether there is any reason for the engine to lack manifold vacuum, I assume that it has sufficient (above 14"). I would check the switch for leaks, check the hoses for leaks, and the connector as well. It is essential to have a cannister, as manifold vacuum changes too rapidly to control the diaphragms. The bigger the cannister, the better, and I suggest a one-way valve on the input to alleviate the possibility that the cannister leaks back into the intake. let's start with that.
