12.7 no heat

there should be hot supply coming off the oil cooler that supply the hot coolant to the heater check for a valve on the oil cooler. the two going to the water pump are returns.

 

Yep, maybe that ones turned off.

 

Kenworth uses VIN (Pete too) over because run out of numbers.
The 2005 T2000 does have a Cat MXS in it.

 

Attached the wiring diagram for cab HVAC. Usually what I do is remove the actuator from the water valve. Mark the location of the shaft, then change temp setting in the cab and see if the actuator rotates. Also check to see if water valve rotates by hand when you have actuator off. You can buy the complete water valve with actuator (P/N SR2000028), just actuator (P/N SR2000045) or just valve (P/N SR2000034). I have been buying most of my A/C parts through a Rush dealer and saving $$$. They have a Rig Tough line that is MEI A/C parts (Air Source). Rig Tough P/N's are 725-2720 (Valve complete), 725-2556 (actuator), and 725-1402 (valve only). hope this helps.

 

just looked at pictures again the yellow handle valves are shut off

 

If it's not the valves/hoses, it could be the hvac system in the dashboard. The plastic flaps in the hvac that control airflow direction or temperature can wear out and fail.