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A/C control problem

Old Feb 21, 2003 | 10:40 AM
  #1  
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bigric
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A/C control problem

In our '92 Bronco, we get some interesting things with the A/C controls. For instance, if it is set to Max, it will turn to defrost under heavy acceleration. Additionally, if it is set to Mix, it only goes to the floor. I know that the system is vacuum controlled, and I've already replaced the control switch behind the function ****. Where else should I check for problems? I know there's some vacuum plumbing behind the ash tray, and there are several door control actuators. Any ideas?
 
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Old Feb 21, 2003 | 10:49 AM
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greystreak92
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A/C control problem

Not certain about the MIX situation but the switching to defrost under heavy acceleration is a loss of vaccuum to maintain the directional vanes. Defrost is kind of the "default" blower position for lack of a better term. If you lose vaccuum to the system the vanes return to the defrost position automatically or they should. I would check for any vaccuum leaks into the entire system on that one.

Could be the MIX problem is a vaccuum line pulled off a control pot and causing the leak that is affecting the rest of the system as well. This is where a good vaccuum diagram from a repair manual would come in handy.
 
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