[porthole]

Look behind the gray doors first, look for the the inside part of the T-handle.

Look to see if the cable jacket is attached to the handle parts. Operate the handle in and out, look to see what is moving. You may also be able to see where the cable travels to the valve. A common problem is the cable jacket breaking free of the handle, frequently that can be fixed with minimal effort.

Try and take a picture of what you see.