Well, it sounds like your 69 has a bath fan similar to my 86. Mine has a handle that is pushed up to open the vent. Then it has a rotary switch that turns on the fan motor. The fan blades are plastic. The fan blade is just pressed on to the motor shaft. The motor shaft has a flat on it that drives the fan blades.
The fan motor will not run unless the vent lid is pushed all the way up. The fan blades it the vent lid. If the fan motor was turned on, but can not rotate, it will trip a circuit breaker or fuse.
A rusty motor does not surprise. Does the motor run? Does the fan blade turn when the motor runs? Can you describe the problem so troubleshoot the problem you are experiencing?
I think 12v
fan motors, rotary switches and fan blades are readily available at RV dealers or on line RV parts sellers. These parts are not Airstream exclusive.