AboutDavid Hill Expertise I can answer questions concerning automotive air conditioning systems, residential air conditioning systems and electrical repair questions.
Experience I have 16 years of experience in the automotive air conditioning arena and am currently an instructor for H.V.A.C.
Education/Credentials I am certified through as a universal technician under sections 608 and 609 of the C.A.A.
Expert: David Hill Date: 7/1/2008 Subject: 1972 chevy monte carlo a/c
Question My a/c system is charged, blows cold air, entire system is new. my problem is no volume when you select max air, the volume stays the same
Answer Ed,
First off... nice car. My second favorite body of all the Montes out there. Planning to restore, or is it already there?
Ok, down to business...
The fan speed circuit is fairly simple if you are using the original controls. If you have upgraded those, then there is a slight difference but the principle is the same. The fan spped switch recieves voltage and when you turn it to blow it sends voltage to the next component, which is a resistor block. This resistor block has anywhere from 3-8 different resistors in it. The lower the speed setting the more resistors it flows through. When set to the fastest speed, the voltage travels through no resistors and sends 12 volts straight to the blower motor. Does your speed of the air differ as you run it through the lower speeds? If so I believe the problem lies in your fan speed switch itself. There sounds as if there may be a crossed connection to where it will not bump it up to that last notch, it is insisting on going through one resistor. I would check the connector at the back of the fan switch and make sure that first there is no crossed connection, if that appears good, then I would look into your resistor block, there may be a cross there that is feeding the voltage through a single resistor. If both of these check out, I would replace the switch itself.
I hope I was of a little help, and thank you for the question.
