Aileron controls seized
 

I own a 1967 C337B model and the issue is that the ailerons are seized. It was parked outside over the winter waiting for it's annual to be done. The AME was busy and it sat for months. Now the ailerons don't budge. Tried penetrating oil and removing cable from servo motor without success. The previous owner informed me that there are tubes and bushings in each wing that corrosion can cause the cables to seize. Where is the located and can it be checked? Next step is to remove each cable from the yoke and see if either the left or right side is free and go from there to try and localize the problem.
Any help is appreciated.

Hope I have successfully attached images showing the aileron control system. On underside of wing out by ailerons you’ll find access panel and once removed see the bell crank and push tube.
I had a problem with servo for autopilot restricting movement. I ended up disconnecting servo connection from bell crank. I have a 400 autopilot. The servo connection will be on the passenger side bell crank.
Also had pulley at wing strut cause resistance that freed up with lubrication. To see these cables wing strut covers come off. The cables run under the floor, up the strut out to bell crank near end of wing.
I would lube everything up before disconnecting cables.
There’s a fair number of twists and turns in the system, try to look at everything which can be a number of access panels and plates. If you take a cable off it could jump a number of pulleys. So I would identify the bind if possible with cables in place.
One of the attachments is a zoom in on the bell crank. Being outside over the winter I would give that push tube attachment to ailerons some attention.
One of the turns is under the plate under the pilot feet where heater vent is up by rudder pedals. You’ll have to take apart that heater vent in the floor to see and lube it.
Make sure nothing hasn’t jumped off a pulley.

Here is the "ailerons stuck" troubleshooting guide from the manual

Thank you for all your assistance! I'm happy the say the ailerons are now working again. The lubrication of the bell crank seemed to do the trick.