Front unit works well and blows cold. Back unit blows but not cool. Where should I start? i am selling the car and this is the only thing not working.

 

2 things come to mind.

1. Make sure the thermostat control is hooked up and to full cold.

2. Expansion valve under passenger seat.

 

I had that same problem. For me it was the expansion valve in the back.

 

there is a solenoid valve under the pass front seat that allows freon to access the rear air unit. if that isn't working, the rear unit will not get cold. the expansion valve is at the front edge of the rear unit (not under the seat-sorrry andrew) and that will also prevent cooling if it is not functioning.

 

how do i access the expansion valve? what do i do after access?

 

remove the rear carpet and move the passenger seat fully forward see if the wires are connected turn on the key and turn on the rear air control to fully cold and turn the fron on as well and see if you hear a clicking noise this is the the ex valve opening if no click then you have to check for current and also see if the plug is off under the console to find this remove either side consle panel and take a peek at the temp setting control for the rear

 

Mine is actually colder in the back.