Suburban water heater issue

Not an uncommon problem on the AC side of this model water heater. Replace the thermostat, wire and the ON/OFF switch. You will need to remove the ON/OFF switch to replace the wire. You can just pry the ON/OFF switch out for the outside. I use a cotter pin removal tool with the 90 degree end. Don't worry about damaging the switch since you are replacing it. The switch is under AMP rated in my opinion and I see lots of burned terminals, just like the wire end on the thermostat.