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A/C controls


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67 Riv w/ a/c, not automatic climate control; after buying a new "control head" as the mechanic said, I saw a kinked vacuum line. The day before I was to take it in, I spliced a new section of line, and after we pumped it up w/ Freon I think it's working well.

Question; the fan has 4 speeds and it seems that the compressor engages in only 2 out of the 4 positions. Also, is it normal to get a better volume of air while the setting is "NORM" as opposed to "MAX"?

Do you think I need a new fan relay? A new switch for the fan, in the control head? Or something else?

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Guest Rob J

Not sure how it is on the 67, but typically my experience over the years with norm, means it refers to fresh air from outside that gets cooled, then pumped into the car. Max referres to recirculate usually, and should result in typically slightly more air volume, and cooler air.

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As soon as the A/C slide control is switched to REC or NORM the compressor clutch should engage at any blower speed. LOW-LOW, LOW, AND MEDIUM speeds are regulated through the resistor bank. When the blower is switched to HI the relay energizes and bypasses the resistor bank to provide full power.

If your clutch only engages on two fan speeds its possible the fan switch is faulty or someone was doing some re-engineering. The clutch engage switch (A/C lever) gets its power from the blower switch when any speed is selected other than OFF.

Before you buy a fan switch you should troubleshoot it electrically to be sure thats the problem.

The volume of air when in REC or Norm position should be the same if the car is sitting still. The blower runs the same and its just pulling inside or outside air. It may sound different but the same amount of air is being moved. If you have a noticeable difference in flow there may be an issue with one of the vacuum doors.

While the car is moving at speed down the road you do get some increased air flow from the "ram-air" effect in the NORM position but not so much in the REC position. I think the REC setting doesn't provide 100% inside air. A small percentage of outside air is let in but its mostly inside air. Probably because so many people smoked back in the day they didn't want the cabin to fill with smoke when set to RECIRC. ;)

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