Auto Air Conditioning & Heater Repair: ac, orifice tube, gmc yukon

Question
2001 gmc yukon. rear ac not cold at all. front ac works fine. i have replaced the rear ac\heater control panel. rear heater works fine. any ideas? thanks, peter

Answer
THE REAR UNIT HAS A SEPARATE ORIFICE TUBE THAT IS BEFORE THE EVAP INLET LINE-SMALLER LINE THAN THE OTHER ONE. IF IT`S PLUGGED UP WITH DEBRIS IT WILL RESTRICT FREON FROM ENTERING THE EVAP.THEN AGAIN,IF THE A/C FREON CHARGE IS TOO LOW THE REAR UNIT WILL STARVE FOR FREON AND NOT COME COLD. RULE OF THUMB-ALWAYS CHECK THE REQUIRED A/C FREON PSI FIRST..YOU NEED SERVICE GAUGES TO DO THAT ..

GOOD LUCK,DAVIDT