A/c Warm In Back Only

[JF1957]

HI, I have a 1999 Burb with two A/C, the front is blowing cold but the rear is warm. His there a valve or something that don't open ?

Thank's

[GMTRUCKTECH]

YOU COULD BE LOW ON FREON ,BUT ALSO THE EXPANSION VALVE FOR THE REAR EVAPORATOR COULD BE CLOGED. GOOD LUCK

[JF1957]

Freon has just been filling up, front is pretty cold, where is that expansion valve for the rear evaporator ?

Thanks

[GMTRUCKTECH]

REMOVE THE REAR PASS. SIDE TRIM PANEL (BIG ASS LONG PANEL UNDER SIDE REAR WINDOW) AND YOU WILL SEE THE EVAP CASE. INSIDE THE CASE IS THE EVAP AND TAPED TO THE EVAP IS THE EXPANSION VALVE. THERE A FEW SCREWS HOLDING THE CASE IN AND i THINK THEY ARE 10MM, BUT DON'T FORGET YOUR WILL NEED TO RECOVER THE FREON FIRST AND REMOVE THE AC LINES UNDERNEATH THE PASS REAR BACKSIDE OF THE VEC BEFORE THE CASE CAN BE REMOVED. ONCE THE CASE IS OUT IT'S HELD TOGETHER WITH 5.5MM SCREWS. REMOVE THE SCREWS AND THE CASE WILL SEPRATE IN HALF AND BAM THERE IS YOUR EVAP. ITS SOUNDS LIKE A LOT OF WORK BUT REALLY IS NOT AS BAD AS DOING A FRONT EVAP. BY THE WAY 9 TIMES OUT OF 10 THIS FIXS THE REAR AC. GOOD LUCK

[JF1957]

Thanks a lot GMTRUCKTECH, know it cost me $ 225,00 to add my freon fill up, so I don't know if I'm going to go on.

Bye

[GRB60]

Have a dealer check for body codes. Mine had a bad blend door to the rear. They did find a code stored on the Body Control Module.

[GMTRUCKTECH]

99 CLASSIC DON'T HAVE HVAC DATA IN BCM.

[GRB60]

Never mind.

[JF1957]

Yesterday with my mechanic neighbor we found two capped hoses near the firewall just below the condensor. So its appear that a problem occurs whit the rear AC a long time ago. Anyway the case is close for me and I thank you all for your help.

Bye