Idle and aircon

[IvegotaCommy]

Trouble with the idle speed. Decided that I have an air leak. Finally decided to go looking for it.

Turn the air con on and I can hear this whistling noise from under the dash. It is throttle position sensitive. Crack open the throttle just a little bit and I can hear it.

I have been trying to work out how the air con and heater system works. Information in the book is a bit sparse. I have the Heater control panel out and on the vacuum switch there appears to be 5 tubes. I assume one of them is vacuum from the manifold. Diagram in the book shows two servos. One for the vent, one for the fresh air/recirculate. So what are the other two tubes for? There must be another servo to direct air either to face level or floor level but I can not see that one. It might possibly be in the heater unit. Any one know anything else? I need to trace out every tube.

As part of the current round of repairs, I tried to fix the heater blower. It works only on the high setting. Culprit looked like the resistor box mounted inside the plenum. Got another from the wreckers (I wanted to finish the job quickly) then removed the old one. Checked it out and sure enough it was open circuit in all but the lowest value resistor. Plugged the 'new' one in and you guessed it, it too was open circuit. Interesting point is that the resistor was burnt out at the same place in each of them. My guess is that this is a common problem.