Circuit Protection Features
The SAM chassis and SAM cab may be equipped with self-resetting circuit breakers instead of fuses. Self-resetting circuit breakers are tripped when they reach 170°F (77°C), then self-reset once the temperature drops sufficiently. When the circuit overload is removed, this circuit protection will self-reset. Some of these circuits require the ignition switch to be cycled off then back on again for the self-reset to occur.
Some ECU's are equipped with a self-resetting circuit breaker removal tool.
Warning: Always wear heat-protective gloves when handling a self-resetting circuit breakers, which can reach extremely high temperatures. Failure to use appropriate heat protection can lead to serious injury.
Notice: Self-resetting circuit breakers can be permanently damaged if improperly handled. Use the guidelines below to handle them safely.
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Disconnect the batteries before removing a self-resetting circuit breaker.
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Use a circuit breaker removal tool to remove a self-resetting circuit breaker. See Fig. . Use of any other tool, including pliers, may damage the circuit breaker.
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Circuit Breaker Removal Tool
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Self-Resetting Circuit Breaker
Fig. 1, Self-Resetting Circuit Breaker Removal
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Never attempt to probe a self-resetting circuit breaker while installed on the SAM Cab or SAM Chassis. Remove the circuit breaker first, or use a non-contact infrared thermometer to measure temperature.