Hi.
I recently purchased a 2010 QX56.
When I crank the temperature dial all the way in either direction, I don't seem to be getting hot or cold temperatures from the vents! Fan is working I've tried on auto, dual auto, a/c on and off.
Also, why doesn't the cooling setting go below 18 degrees Celsius? I would just like to vent outside air sometimes.

Thanks,
Mitchsky

60 degrees is as low as it goes. that is basically wide open outside air when NOT on HVAC, so if you want outside air you will get it. as you turn up the temp, the system mixes in the heater core to get the desired temp.

as for your HVAC issues, well that's a rabbit hole that is hard to figure out over the internet.

if you recently purchased, is it under a grace period? was it through a nissan/infiniti certified program or 3rd party/lot?

how many miles? did you do a carfax? may be worth finding out what the car has been through.

mileage may answer certain things so cant really help without more detailed info.

but things to check:

compressor
check for obd codes
leaks in the sytem
too much oil in the hvac system
too much refrigerant in the system
receiver/dryer is faulty/damaged
heater core could be faulty
etc etc etc ....

Thanks for replying.
It has 125,000 miles on it.
Bought from third party lot. They agreed to take a look at it later this month.
A/C doesn't seem to work.
Defrost gets hot on passenger side, not on drivers side. Drivers side doesn't blow out of the vents as well as the passenger side does.
I will check the floor vents and rear vents when I get a chance.
I have a Carfax , it looks fine.
It shows that they did an evacuation and recharge of the system in June.

could be low refrigerant/perhaps a leak. make sure they check ALL the joints on the AC lines. there are some that go under the chassis in the rear that could be faulty.

also could easily be the hvac doors stuck open/closed.

is the blower speed/force of air moving air or does it feel weak out of the vents? im speaking about the FORCE of the air not how cold or hot.

a way to test the hvac doors in the dash:

set mode switch to top vents /dash
set fan speed on HIGH

then wait 10 ish seconds between each "mode" (i.e. change a mode and stay in that mode for about 10-12 seconds), press the mode button to change from top to dash to floor and back all whilst keeping the fan speed on high.

could unstick doors if they are stuck closed. may not yield any fruit but worth a try.

They got the a/c working in the front. They say the lines to the rear are capped.
Passenger side vents blow harder than driver's side. I am thinking that it's probably because of the cabin filter.
So, they got the front a/c working, on the way home, I encountered some rain and needed to defog the windows. For some reason there was no heat now! They agreed to look at it again next week.
Today there is heat front and back except for the driver's area.
What's going on?

hard to tell what's going on over the internet.

cabin filter is not going to cause one side to blow harder than the other. you may not even have one in there. easy to check though. reason one side blows hard than other is maybe due to the door actuators inside the assembly. if a door is stuck closed in there, it can force air in one direction. you can test this by turning the fan speed on high and cycle through the MODE switch, staying in each MODE for about 10 seconds then moving to another MODE. AC does not need to be running, this will test to see how the doors inside the assembly are working and if any are stuck...

lines capped in back? they could be leaking.

are you taking it to an infiniti dealer or some 3rd party?