Is there a front expansion valve for the a/c

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.

Kia Sedona expansion FRONT valve located under dash, behind glove box, fan and coil. Evacuate freon first. Disconnect Freon lines from firewall., Lay right front seat back to flat horizontal position and lay on top or totally remove the seat for easier working access. Remove under dash cover, fan, glove box, coil housing, remove coil mounting bolts, remove old expansion valve. (Inspect old valve, if debris inside, blow out coil before installing new valve. If visible debris best to consider replacing REAR expansion valve and DRIER/FILTER in front of radiator too and blow out all lines and coils while servicing.) Use compressor oil to lubricate "O" rings on new FRONT or REAR expansion valve, install valve bolts, reinstall coil bolts to FRONT firewall or REAR frame, reconnect freon lines to firewall in engine compartment. Evacuate AC system, install freon (35 1/2 ounces, nominal 3 pounds), check system for leaks, check for proper operation, enjoy.

Give some more details of the problem.

the front expansion valve is located with the evaporator ,
a big job. the rear is the same , just easier.

they no longer use expansion valve.it has been replaced by a FIXED ORFICE TUBE

Verify that the temperature control inside the vehicle is actually working and not stuck in the hot position.

the expansion valve is in the rear ac housing and it is bolted directly to the rear evaporator. it is an actual expansion valve and not an orifice tube. the part is about $45. the interior on the passenger side has to come out along with the entire rear ac sytem.

the system could still be low on freon even though front works

The rear air has an expansion valve in the rear of the cargo area right next to the rear evaporator. There is no orifice or filter between the condenser and the rear expansion valve so if there is any debris in the line it will clog the expansion valve. The orifice under the hood is only in the front circuit so if the front is cooling and the rear is not, most likely the expansion valve is clogged and needs to be replaced.

There is a factory service bulletin on how to r&r the expansion valve. It requires some cutting since they did not design it to be replaced. Part of the service bulletin is adding an inline filter at the outlet of the condenser before the front and rear flows divide. That will keep the rear from clogging up again.

I have a 94 Suburban and I had to do this in about 1998. With the filter I haven't had any problems since.

Probably plugged or failed expansion valve on rear evaporator. Both front and rear are plumbed in parallel so if the front is cold, a problem with refrigerant flow at back unit almost has to be in the expansion valve.