Re: code 52, +Evap sensor shorter ground etc.
Code 52 = recirculation door travel too large. This kind of message normally means that the door or door connection is broken and that the actuator motor continous rotating. I would reset the system (disconnect the battery for 5 mins.) and operate the system and see if it comes back. If yes, remove the blower motor (at passengers footwell) and look up to the recirculation door. Some people just fix it in place with a wire. Let me know which fault codes show up.
Normally when there is no heating, the problem is with (one of) the blend doors. But you don´t have any blend door message sofar. When you move the temperature control knobs, do you hear the actuator motors run?
Regarding the cooling, the evaporator sensor is as far as i know only used on 2004 WJ´s, but i can be wrong. This sensor is mounted on the evaporator core (inside the HVAC housing) and prevents freezing of the core. On your jeep that function should be taken care of by the low pressure switch (mounted on the accumulator). That switch could be open all the time due to a switch problem, or when the A/C precharge is too low. The switch can be changed without loosing refrigerant, because it has a schräder valve in the fitting. If your jeep really has the sensor on the evap core, then the whole HVAC housing has to be removed and opened up= complete dash removal.
JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks /
Pirelli Scorpion ATR 245/65/17/
Transgo reprogramming shiftkit.