Overheating Switch
 
If the 8 Amp fuse for the overheating switch has blown, check that the switch has moved to its original position before a new fuse is installed.
- Disconnect black-red cable from terminal with short circuiting fuse to overheating switch. 
- Test overheating switch with an ohmmeter connected as shown. The switch must not have continuity. 
- If, when the heater is cold, the overheating switch completes the circuit, the switch is defective and a new one must be installed.