[Class system, compressor not coming on]

Might be a stupid question but you didn’t say you were pressing the high medium or low auto or trying to adjust manually. Just toggling between front and rear will not activate the compressor, only show you the current pressure in the system.

 

also did you re solder the entire board or only what you thought were questionable joints?

 

Pretty much the whole board was touched up. no matter what I press the compressor wont kick in. I can hear and feel the front solenoids click though and the display shows no errors

[Class system, compressor not coming on]

So I have re-soldered the board connections and all looks good. I have also checked the operation of the compressor pump as well as the solenoids and all of them work also. The class display shows zero pressure front and rear but no error codes. if i cycle between front and rear I can hear the solenoids click but the compressor wont start