The non-volatile Latching Temperature Switch relay monitors a normally-closed-low temperature switch. It incorporates a bistable relay that retains its state during power failures. LEDs indicate the status of the relay, and connections for an external reset button are provided for manual control. The reset inputs of multiple units may be connected to a single push button as long as proper polarity is observed when making the connections. Under normal conditions the temperature switch opens, the relay energizes and latches on until the temperature switch re-closes and the reset button is pressed. The unit will function properly with zero to 2k Ω of resistance in series with the temperature switch.