Ac/heater controls

terry march

Active Member
What makes the temperature control switch from defrost to vent air? The reason why I'm asking is that the only way I can get mine to switch to defrost is to pull the vacuum line off of Vacuum Actuator under the dash. How can I remedy this?
 

firstofeight

Active Member
Since car type is not mentioned, we [ I ] can only guess. Mention of vacuum line is a clue. Guessing the vacuum controller is bad and not changing as it should. Happened on my '92 Roadmaster. Controller from a junk yard Caprice worked.

Ben
 

terry march

Active Member
Since car type is not mentioned, we [ I ] can only guess. Mention of vacuum line is a clue. Guessing the vacuum controller is bad and not changing as it should. Happened on my '92 Roadmaster. Controller from a junk yard Caprice worked.

Ben
1966 Buick Riviera.
I can pull the hose off of the vacuum accumulator and plug it. Then the air works on defrost put it back on then it switch back to vent air.
 
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