Power Wheel Chair Repair

I have a disabled friend with a off brand power chair that needs some work or possibly just instruction as there is no manual.
I have contacted the distributor Sigma Med and they will not respond.
The individual systems have been checked and seem to be fine, but it is possible the controller is somehow locked or defective.

Anybody with knowledge of these systems, your help would be greatly appreciated or any resource.

Have you tried an online search for an operating or instruction manual for the chair.

Yes but I am not able to find the manufacturer

Being in a power wheelchair myself I have known other distributors with knowledge of fixing or may have some idea of who could fix it even if they don't sell that brand.  Just a thought,

My friend gave up on it and trashed the chair

OK, thanks