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Old 07-15-2014, 08:53 PM
8 posts, read 33,733 times
Reputation: 12


1991 Chevy Caprice 5.0L - A/C Controls Question
I am in the slow process of restoring this car ( belonged to my late Father ) . The A/C is one of those chores .

The controls have a bottom lever that goes from cool to heat . I think this has a mechanical cable that operates a blend door ?

There is a vacuum operated " hot coolant " valve , under the hood . I am guessing it is also operated by the bottom lever ?

Looking at a diagram of the control unit shows a double hose that , if I recall , is labeled as going to a water valve .

When I move the bottom lever , I hear a noise that sounds like it may be a blend door opening and closing . So , at least the blend door may be working correctly .

There is also an upper lever on the control unit that goes from max A/C on the left to defrost on the right . It seems , no matter what position that lever is in , part of the air is coming out the defrost vent & part coming out the dash A/C vents . Some may also be coming out the bottom heater vent ? Have not checked .

So , this control is not working properly .

The diagram of the control unit shows a 5 hose connection , which I figure are 5 vacuum hoses ?

Before I start messing inside and under the dash , I wish to verify that I truly do have good vacuum going to the control unit . Does anyone have a drawing / diagram if the vacuum system for this car ? And I would appreciate info on where the source vacuum line for the A/C controls , plug in to receive engine vacuum ?

Any other info or tips would be much appreciated . :-)

Thanks ,
God bless
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