FAQ-35

MUST READ for those with rear A/C.

If you are using your A/C and have rear air conditioning, NEVER shut the rear blower off and never run it on low speed. If you get too cold, don't shut that rear blower off or put the fan speed on low, open a window and mix some warm air with the cold air inside. As a matter of fact, if I were King, I would eliminate low speed on all rear fans, during use of the air conditioning . . . and here's why.

The air conditioning compressor cannot handle liquid on the suction side. So the front AC unit dumps or sends it's refrigerant (or Freon) back to the compressor via a can called an accumulator where any liquid left falls to the bottom and the gas rises to the top and then is fed back to the compressor. This is important because the compressor cannot compress a liquid, only a gas.

The rear AC unit has no such can or accumulator so unless we turn the liquid to a vapor, (or evaporate) the Freon in the rear air conditioning unit by using the rear fan, all we end up feeding the air conditioning compressor from the back air conditioning unit is liquid Freon which wipes it out. The air conditioning compressor cannot handle sucking in a liquid and compressing it, it can only handle or compress a vapor. That's exactly why so many rear air conditioned vans, Suburbans, Explorers and other SUVs have major air conditioning problems year in and year out.

This isn't a new problem, however, it's been only recently that GM has determined that the absence of an accumulator for the rear air conditioning unit can and will cause these problems. They always thought folks would use the heck out of the rear air conditioning and never considered the drivers would run with the rear unit fan shut off.

So wives, tell your husband to stop running the air conditioning with the rear blower on off or on low. Tell him to run the fan on medium to high.

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