Help needed with 1998 volvo B10M coach

this machine wont put air to any of the airbags when she is started. Any ideas about how to solve or what the problem might be?
I thought it might be the brain so i tried another one on loan to no effect. She is filling the clocks ok, and a while back she would fill the bags on one side but not the other. She does’nt seem to be putting the power to the brain to the airbags. Any help much appreciated

Do you have any air going to the level valves and do you have power to your ferry lift switch

Volvo B10m’s after late 1996 have electronic air suspension, the electronic control unit needs a signal from the alternator and if the alternator is not charging the electronic air suspension won’t work