Temperature Indicator
System consists of a "TEMP" or "ENGINE" lamp and a normally open-to-ground temperature sensing switch. When coolant temperature reaches approximately 249°F (121°C), switch closes circuit to ground, turning on the indicator lamp. As a test of proper bulb operation, the lamp will also turn on with the ignition in the "START" position.
NOTE:
On models with Automatic Temperature Control type air conditioning systems, the temperature sending unit has 2 terminals. The terminal marked "R" (gauge equipped) or "C" (indicator lamp equipped) provides a ground circuit for cold engine override (below 115°F (46°C) engine temperature) of heater blower motor.