I replaced the head gasket recently on this van before the air conditioner worked both in front and back now it only works in front and its blowing hot air in the rear also my vents wont switch from defrost position what would cause this.
Check your fuses first. (most likely cause)
1) Fuse #21 inside fuse panel 10A fuse.
If this checks out, then you will need to trace power to and from the Control Panel switch.
If that checks out then you will need to check for power and ground at the blend door actuator. If you have good power and ground, the next step would be to replace the blend door actuator. (this applies for the front and rear)