A disconnect system to be connected between a DC power source comprising a battery system and a load comprising a load of a vehicle, the disconnect system comprising: a master switch defining a first master switch terminal electrically connectable to the DC power source and a second master switch terminal, the master switch manually operable between a normally open state and a closed state, the master switch configured to stay in the closed state so long as current flows between the master switch terminals (80, 82) and reset to the open state when current no longer flows through the master switch terminals (80, 82); at least one relay switch defining a first power terminal, a second power terminal and a first control terminal, the first and second power terminals (90, 92) electrically connected between the second master switch terminal and the load to form a power circuit, wherein the at least one relay switch is switchable between a normally open configuration in which current is prevented from flowing between the first and second power terminals (90, 92) and a closed configuration in which current is allowed to flow between the first and second power terminals (90, 92); at least one thermostat switch secured to a sensed portion of the load; and a control wire connected at one end to the at least one thermostat switch and at the other end to the first control terminal of the at least one relay switch to form a control circuit, wherein the master switch, the relay switch, and the at least one thermostat switch are configured such that: when the at least one relay switch is in the closed position, current can flow through the at least one relay switch to the load and through the thermostat switch to the first control terminal to hold the at least one relay switch in the closed configuration; when a temperature of the at least one thermostat switch reaches a predetermined temperature level, the at least one thermostat switch prevents current from flowing to the first control terminal and thereby resets the at least one relay switch to the open configuration to prevent current from the DC power source from flowing to the load and thereby prevent current from flowing between the master switch terminals (80, 82) and reset the master switch. a master switch defining a first master switch terminal electrically connectable to the DC power source and a second master switch terminal, the master switch manually operable between a normally open state and a closed state, the master switch configured to stay in the closed state so long as current flows between the master switch terminals (80, 82) and reset to the open state when current no longer flows through the master switch terminals (80, 82); at least one relay switch defining a first power terminal, a second power terminal and a first control terminal, the first and second power terminals (90, 92) electrically connected between the second master switch terminal and the load to form a power circuit, wherein the at least one relay switch is switchable between a normally open configuration in which current is prevented from flowing between the first and second power terminals (90, 92) and a closed configuration in which current is allowed to flow between the first and second power terminals (90, 92); at least one thermostat switch secured to a sensed portion of the load; and a control wire connected at one end to the at least one thermostat switch and at the other end to the first control terminal of the at least one relay switch to form a control circuit, when the at least one relay switch is in the closed position, current can flow through the at least one relay switch to the load and through the thermostat switch to the first control terminal to hold the at least one relay switch in the closed configuration; when a temperature of the at least one thermostat switch reaches a predetermined temperature level, the at least one thermostat switch prevents current from flowing to the first control terminal and thereby resets the at least one relay switch to the open configuration to prevent current from the DC power source from flowing to the load and thereby prevent current from flowing between the master switch terminals (80, 82) and reset the master switch.