ok, I already found the solution: [URL]   Disabling in device manager, then start cust tool kit, then enable in device manager en you get a button 'enable radio'
I have a problem with a Latitude 5420 notebook.  The supplied WWAN module is a 5821e Snapdragon LTE module. According to dell this module (modelnr 555-bfld) should be compatible with the 5420, but no drivers are available. I can find drivers searching through other notebook modules, these drivers work but with some I cannot enable the mobile network, with others I only get 'no service' after entering the pin. Also, this module has 4 antenna-connectors, while the 5420 only has 2 antenna's.  I connected the outside connectors (main + aux1)
Latitude 5420 driver for 5821E WWAN module