Only warm air comes from the vents Jeep Cherokee

Jeep Grand Cherokee

Replaced the a/c compressor, drier, and expansion valve. Then I replaced all the seals and o-rings. Next I applied a vacuum pump, ran the pump until it reached 20 lbs. I left the manifold gauges on and waited for about 45 minutes. The system held the vacuum at 20 lbs. I then put 24+ ounces of refrigerant in it. The compressor kicked on while I was putting in the first can of R134A. However, the electric cooling fan doesn’t come on with the compressor, and the a/c is still blowing warm air. I have also replaced the pressure switch. The compressor runs constantly while the a/c is on, but only warm air comes from the vents. I don’t know what I am doing wrong. It is a 2009 Jeep Grand Cherokee.


Probably not doing anything wrong. Working on your air conditioning can be difficult even for an advanced mechanic. I hope you added in some PAG oil as required. 24 oz of R134a seems a bit high. Let me look it up in the manual to see how much it is supposed to hold. Overfilling the system can cause an issue as well. Manual states 24 oz. It also states you need 4.4 oz. of PAG-46 oil. I do not think this is your issue though.

2009-jeep-grand-cherokee-air-conditioning-specs

I think you may have more than one thing going on here. The hot air coming out is usually a failed mode door actuator deep in the dash. At least that is the case for most of these Chrysler vehicles I have worked on. As for the fan not coming on, I am thinking faulty Relay but let me look that up also. (see diagram below) Yep, it appears the system is equipped with fan relays. I would check those out. You also may want to test the fan motor itself just to rule that out. I like to use my Power Probe for this. It allows you to apply battery voltage and has a built in circuit breaker so no worries about blowing fuses.

2009-jeep-grand-cherokee-cooling-fans-wiring-diagram

HVAC BLEND DOOR ACTUATOR R&R

LEFTHAND SIDE
Warning: Disable the air bag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the battery (ground) cable, then wait two minutes for the air bag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the air bag system. Failure to take the proper precautions could result in accidental air bag deployment and possible personal injury or death.
Single zone heater-A/C system is equipped with a single blend door actuator. Dual zone system has two blend door actuators, one for driver side blend-air door and one for passenger side blend-air door.

  1. Disconnect and isolate ground battery cable.
  2. Remove instrument panel silencer from driver side of instrument panel.
  3. Remove three bolts (1) that secure blend door actuator (2) to lefthand side of HVAC air distribution housing (3), Fig. 1.
  4. Remove blend door actuator from air distribution housing and disconnect HVAC wire harness connector (4) from actuator, Fig. 1.
  5. Remove blend door actuator from vehicle.
  6. Reverse procedure to install.
    RIGHTHAND SIDE
    Warning: Disable the air bag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the battery (ground) cable, then wait two minutes for the air bag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the air bag system. Failure to take the proper precautions could result in accidental air bag deployment and possible personal injury or death.
    Single zone heater-A/C system is equipped with a single blend door actuator. Dual zone system has two blend door actuators, one for driver side blend-air door and one for passenger side blend-air door.
  7. Disconnect and isolate ground battery cable.
  8. Remove glove compartment from instrument panel.
  9. Remove three bolts (1) that secure blend door actuator (2) to righthand side of HVAC air distribution housing (3), Fig. 2.
  10. Remove blend door actuator from air distribution housing and disconnect HVAC wire harness connector (4) from actuator, Fig. 2.
  11. Remove blend door actuator from vehicle.
  12. Reverse procedure to install.
2009-jeep-cherokee-blend-door-actuator-fig-1