Unless it is something simple, then unfortunately a Nissan consult 2/3 diagnostic tool will be required to get an accurate diagnoses., however the tool is only as good as the guy on the job.
Fortunately I do have a selection of preowned Roadster roof parts in stock, however I would require your VIN to verify that they were compatible with your vehicle. I have the following in stock. All are preowned. The list is not exhaustive.
Roadster ECU
Roadster BCM
Roadster IPDM
Roadster Roof ECU
Roadster fuse boxes.
Unfortunately I can not take returns on any of these parts due to the nature of the components, so it is imperative that the diagnoses is correct.
Let me know if I can help you further.
Alex.