I have read a few post on here but still not clear,do the 2002 dodge durango have dual AC?I do have rear ac control but there is cool when I turn on the ac up front.Now I have read that there is a vent door in the rear of the truck by the 3rd seat.Just want to be clear on is that i need to b to fix this.

 

I'm somewhat confused by what you're asking but what it sounds to me like, yes there is dual zone A/C control. The front controls the front and the back controls the back. They both draw air from the same area and the door in the back is just a direction door that directs air from either upper ducts or down by the feet.

 

sorry if I was not clear,With the air on I am getting cold air in the front but my back vents are blowing cool,so I am asking what can I do to figure out y my rear is not blowing cold like the front,I also checked the lines running to the back and they r not cold either.(the lines under the truck)

 

since you state that the front DOES get cold and the rear does NOT i would say its a blend door in the rear, if you check the lines you have to remember to check the a/c lines not the heater core lines, the a/c lines will be stiff tubing, not hoses iirc.

 

correct i did check the ac lines and they r not cold,so would it still be the blend door

 

hmm, if the a/c lines are not getting cold that would imply to me that refrigerant isnt flowing through the lines, the only place i can think of for a blockage to occur is in the expansion valves (the only place i can think of that would only affect the rear system), since both systems run off the same compressor we know that is fine.

First, before opening the system up i would suggest having a shop put gauges on the system to make sure its still full, id imagine if its low on refrigerant that this could occur (its just a gut feeling but its worth checking into IMO)

 

I have a pressure gauge to check the system and it is good,now I am puzzled because is you r looking at the engine and follow the line to the fire wall that is where they split to the inside of the truck and the other goes under the truck to the back,well at the fire wall is where it all starts.The 1 line is cold and the other at the fires wall is not cold.now I cant remember what post I read but people keep talking about a by pass valve that is on the fire wall,or maybe it called a H valve?not sure of the exact name (expansion valve)

 

Sometimes the rear HVAC unit blend door develops a problem. This door blends air from the rear heater core and ac evaporator, to get the temperature you set on the controller. So if you adjust your rear heat/ac temperature setting, do you get different temperatures? If the temperature doesn't change as you adjust the ****, I'd look into a blend door problem. Make sure the engine is warmed up before you test this.

 

If the lines are warm leading to the rear evap, that could eliminate the blend door as a potential problem. I agree with Shrp that it may be the expansion valve. I think low refrigerant levels would affect both front and rear.
When you checked the pressure, did you check both high and low sides? Or are you using the cheapo low side gauge that attaches to a can of R-134a?

 

Thanks to all for helping me,I only checked the low pressure side.But like I said earlier the front ac is ice cold,nothing from the rear even if I adjust the setting in the truck on the ceiling from warm to cold,the heat works fine it is just no ac.