the retractable overhead guard has some switches to keep you from lifting too high with no overhead protection, these may be your problem, have you checked their operations?
truck_tech's question about the contactor armature pin is still valid and can not be accurately checked without disassembling the contactor (and already knowing what you are looking for) to confirm the guide pin is still in place and correctly guiding the armature stroke. however if you are not getting a positive signal to the contactor coil then the search should begin with that signal.