A/C help

[iam326]

Hey legends, 97 HDJ81 with no A/C. Low pressure switch is good, compressor kicks on when 12v is applied, switch illuminates in the cab, and replaced the A/C amplifier. What should I check next?

 

[OM617YOTA]

What's it doing or not doing? Have you checked to make sure the system is appropriately charged?

 

[iam326]

What's it doing or not doing? Have you checked to make sure the system is appropriately charged?

System is charged. The compressor doesn’t come on when a/c button is pressed