T4050 Air conditioning compressor not coming on

[cecil55]

The air conditioning on my T4050 is not working. I checked the system and there appears to be a sufficient amount of refrigerant but the compressor will still not engage. Anyone know if there is a fuse somewhere to check or what else could be causing the problem? Thanks

 

[Tx Jim]

How you go about checking pressures if compressor clutch won't engage? I located a resister close to blower motor in parts schematics. Have you checked for a blown fuse or tripped circuit breaker?

 

[cecil55]

How you go about checking pressures if compressor clutch won't engage? I located a resister close to blower motor in parts schematics. Have you checked for a blown fuse or tripped circuit breaker?

I just had a gauge on the low side port. There is no fuse for A/C that I can't find in main fuse box.

 

[Harry in Ky]

A/C fuses and relays, probably aren't in the main panel. Look on the cab post between right side door and side window.
Just curious, what was the pressure you say was "sufficient" on the gauge you were reading? Do you recall the approximate ambient temperature the day you were working on it?

 

[LouNY]

Or check for power to the low pressure switch, with the key in the run position, the fans on and the AC selected.
It may need to charged higher to make the low pressure switch.