CAT TL 642c AC

Hi ,
I have a CAT TL 642 c with an AC problem.
It appears the fans located on the roof evaporator unit had seized and now after replacing them with new ones they are not powering up, to cool the refrigerant?
I believe there is a relay and assume there is also a fuse? can someone advise where this is located and what to look for.

Please help.

Regards Andrew