My friend and I both own Dodge Diesel trucks and we are both having a/c problems…cool air comes out of driver’s vents, but only lukewarm air comes out of passenger vents…doesn’t seem to matter what setting the control is on either. HELP…we live in ARIZONA!!
i had the same problem on my car.it was low on freon /134a.so i took it to the a/c shop they purged the unit and added 134a oil and leak detector.you might have a leak in your a/c system since it is a closed unit.their is the blend doors could be stuck.
Check the vacuum pump and the vacuum lines. Since diesel engines cannot use manifold vacuum there is usually a separate pump to supply vacuum to all the HVAC actuators. This can be an engine driven pump or an electrical vacuum pump.
what years?
the new stuff run servos not vac.
may just need to pull HVAC codes.
or a simple reset.
or check pressures(ahhh! theres an idea).