Don't have a pic but I would also advise removing the plastic face cap from the linkage motor assembly. You will see three grooves usually gummed up and dirty with black grease and grime. Give it a good spray with carb cleaner but be careful not to disturb the thin contact guides in the grooves.. refit the cover.
When the guides are gummed up, they loose contact, the motor works harder and as a result everything gets overloaded and contacts burn out!
Don't just replace the issue, cure the initial cause too!