Any suggestions or has anyone heard of this before?

 

Per the diagram, it's on the driver's side of the assembly, near the driver's blend door motor. So left side, above the drivers feet on the side of the airbox, maybe forward and slightly above the blend door. I haven't had my nose down there yet, just going by the diagram. The workshop manual may have a picture of it installed, certainly worth a look.

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The FR and arrow at the top right point to front of car, so the parts assembly diagram view of the airbox is oblique from passenger side, rear and a little above center axis.

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That thermistor is not a normal failure part. While it might be interesting to test it, it's unlikely to be the cause of your symptom. It's intended use is to prevent ice accumulation in the evaporator. A telltale of that is a big puddle on the garage floor after you stop the car. The evaporator drain is through the tub under the car, behind the firewall and slightly left of center. Ice in the evaporator melts and the water drains out there. Another telltale of ice in the evaporator is that airflow is blocked by the ice in the coils and fins. Airflow reduces noticeably, and the fan speed will increase as the system continues to try to cool the cabin. On an extended drive, you can switch off the AC compressor with the console switch, and you'll feel the airflow slowly restore as the ice melts. The first flow will be pretty humid and may have a musty fragrance, as the melting ice evaporates from any dust now mud cake in the coils.

A much more common cause of your less-cooling symptom is incorrect refrigerant charge level. The system protects against low charge level via a pressure sensor in the suction side of the system plumbing. Normally, the compressor cycles on low load as determined by that sensor. With low heat available boil refrigerant in the evaporator, the pressure in the system drops. With low load and low pressure, less refrigerant volume is moving, and there's a slight risk of not carrying sufficient oil around to the compressor again. The lower pressure also means lower boiling temperature in the evaporator, therefore a bigger chance of ice-up.

If you've had the system serviced recently, I'd question the amount of refrigerant put back in. If it was DIY 'recharged' or 'topped up' with a can from the parts store, the charge is unverified. If the system refrigerant charge has dropped, hardly unheard of in a ten- to fifteen-year old car, it may need to be serviced. Recover the old refrigerant, evacuate the system, and put the correct charge back in by weight. If you don't have all the equipment to do this, it's worth paying someone who does do the service for you.