The low coolant lamp in diesel vehicles illuminates in order to indicate that the radiator has a low coolant level. Battery voltage is available to the engine coolant level indicator through CKT 39 (PNK) from GAUGES fuse 4 when the ignition switch is in the START or RUN position. The low coolant level indicator module is grounded through CKT 150 (BLK) at ground G200. The low coolant level indicator module send a signal through CKT 1478 (LT GRN) to the low coolant level switch. When the coolant level drops below the low limit, the low coolant level normally open switch then closes completing the path to ground through CKT 150 (BLK) to ground G105. The indicator lamp will illuminate and continue to stay on until the repair is completed.