Need know where expansion valve is on 2007 nission quest

You need to have a shop put guages on the a/c system and check the pressures. It may have restriction in the system like a bad expansion valve or if the accumulator has never been replaced the system get low and moisture enters the system. It can freeze up causing cooling problems. Also check to see if the electric fan on the radiator comes on when the a/c is turn on. If not then it is your problem

Is the system full of freon ?
The rear ac uses an expansion valve, and the front ac uses an orifice tube. One system can work independently of the other.

Yes it's very true, change the front one and you will not have any further problem

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more than likely you have air in the system,,,make sure you take the bleed valve fitting out of the expansion tank feeder line..crank the car up and turn the ac on wide open.you should see bubbles flowing from the removed expansion feed bleeder screw.When the bubbles stop place the bleeder screw back into the housing.Let me know.

Go under the hood see if the low side gets cold while the AC is on. If the lines are getting cold but the blower do not put out cold air then that means the heater and the ac is mixing somehow. Find out why, if you can't find the problem why the heater is mixing then just put a temporary cut off valve along the heater hose,, those valve are availabe at auto parts. You can just open it back up when winter comes again. Second diagnose, make sure it is not overcharged. The low side pressure should be around 35 psi or so. Make sure the lines are not restricted or blocked. Check the expansion valve. one side of the hose to the expansion valve should be hot, then the other side is cold. This is on the high side (smaller tubes). Comment me again so we can go further if we need to.

I believe they only stopped using freon last year in vehicle ac's. That is what it sounds like is the problem.

Above solution is correct, had the same problem with mine and it was the expansion valve.

sounds like head pressures to high possible expansion valve plugged or bad

if u have a restriction in the condenser or the expansion valve thi will happen needs gauges put on ac to see which is ur problem

either the freon charge is about 1/3 low, or the expansion valve needs to be replaced. Freon is getting into the evaporator, but not in great enough volume to cool the air unless it is coming in cool to start with. check your ac charge, and if it is full, then have it emptied, change out the expansion valve, and recharge it