Freightliner HVAC unit discharge Temperature sensor voltage > normal

can someone tell me please the location of the HVAC unit discharge temperature sensor

 

Can someone please tell me the location for the HVAC unit discharge temperature sensor on a freightliner columbia.

 

What about the sensor in the evaporator (dash) how would you diagnose it, replaced sensors and the harness going to the ac control unit. Ac keeps freezing cause it’s not being cycled off by the temp switch?

 

I don’t know how to test it. But if when you unplug it, compressor should turn off. I’d remove it from the evap, I’m assuming it’s a probe type. Take it out, leaving it plugged in. See if the compressor turns off once the probe is removed from the evap. You could put an ice pack around it once removed, see if that makes the compressor shut off. Maybe you’re just a little low on refrigerant. Makes the lines freeze up, and compressor run constantly. Other possibility is a clogged expansion valve. Assuming the correct amount of refrigerant in system. Manually turning the compressor off till it defrosts. Turning it on and works till it freezes up again. Sure sign of a stuck expansion valve. Might be getting stuck from tiny (less than a pinhead) frozen moisture ice. Sometimes turning on and off can clear it out. Helps to install a new dryer if moistures the problem. I’ve never had a evap sensor get stuck in full time. The 2 times they’ve failed on me, the compressor wouldn’t turn on, I guess you could unplug it, use a jumper wire to engage compressor. Should work. Un jumping it, compressor should go off. Plugging sensor back in, compressor never goes off, might point to a bad sensor. That’s only if everything else is right. I’d definitely check the refrigerant charge amount first. My thoughts are the sensor goes bad usually because of a broken connection, not a constant hot wire.