where is Thermal Expansion Valve located on 2002 Chevy Tahoe?

rear a/c does not blow cold, but the front does.

faulty or clogged expansion valve.

The valve is in one of the ac lines . you are looking for the line next to the fire wall that has a large fitting and about 2 to 3 in. long expansion in it. in other words the line will be big and then get small.

It requires removing the evaporator. Removing the evaporator requires taking out the case assembly.
Remove the evaporator core.

Carefully remove the sealer packed around the Thermal Expansion Valve (TXV). Reuse the sealer on the replacement TXV.

Important: Note the mounting location and the orientation of the tube on the core.

Remove the clip retaining the capillary tube to the evaporator core.

Disconnect the evaporator tube connections from the TXV.

Remove the TXV from the tubes.

Now clean the screen on valve.

And reinsert.To reinsert.

Install the TXV to the tubes.

Connect the evaporator tube connections from the TXV.

Tighten
Tighten the tube connections to 28 N·m (21 lb ft).

Important: Install the clip and the tube in the location and the orientation as noted during the disassembly.

Install the clip in order to retain the capillary tube to the evaporator core.

Pack sealer around the TXV in the manner found during the disassembly.

Install the evaporator core.

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A professional techs job.It requires licensed tools.Which the car garage techs and professional tech or the car dealers have.Its not at all time consuming job, but requires proper tool.

The expansion valve is inside the cabin in the heater assembly or under the hood where the high side line goes into the firewall. If it is inside it's very hard to replace. Outside is not too hard if you have all the A/C tools (like manifold gauges, evacuation pump, R12/R110, etc.)

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You can see the expansion valve on the ac line

What is happening is that when the valve fails, it is no longer able to drop the pressure of the freon passing through it...

The rear of you truck will need to be disassemblied to gain access to the valve..

First off, you will need to discharge the A/C system and disconnect the A/C lines that go through the floor to the rear evaporator..

next, you will need to remove the rear interior trim panels on the passenger's side to get access to the heater box.

Once you are there, you will need to unbolt the box to get to the rear core...I memory serves, you can leave the heater core connected and just pull the evap. core

Once you have the evap. core out, you will be able to unbolt the expansion valve...

If you are not tech savvy, get it done by professional.

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