What parts do I need to fix this problem?
Air condictioner and Heater work good on drivers side, but only heat comes out of
passenger side and with the tempeture is close to 100 degrees outside it is miserable. I
cant figure out what could be wrong.
Could be a failed blend door actuator. Your vehicle has separate controls for driver and passenger heat/AC controls. Since you have heat and AC, the heater core and AC condenser are working fine. You most likely have then a failed blend door for the passenger side. I'd lookup guides for your specific model/year vehicle on how to swap out a bad passenger-side HVAC blend door actuator.
A Grand Prix had that problem and I thought it was the blend vacuum actuator ... after wrestling the new one in that left me with an arm looking like an encounter with a Pit-Bull ... it turned out to be the rotary position switch had flattened O rings that were blocking the vacuum ports
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