Temperature Indicator (1968-74)

Place a thermometer in coolant in radiator filler neck. Start engine and allow it to run until the thermometer reads a minimum of 180°F. The instrument panel gauge should indicate within the normal band.

To test gauge proceed as follows: Disconnect gauge lead from terminal at sender unit. Connect lead of a 12 volt test light or positive lead of voltmeter (20 volt scale) to gauge lead that was disconnected from sender unit. Connect other lead to a good ground, turn ignition on. A flashing light or fluctuating voltmeter indicates instrument voltage regulator is OK and gauge circuit is not interrupted.

If a pulsating voltage is shown but gauge is not accurate perform a calibration test. If light stays on, or voltage reading is steady, replace IVR. If no voltage is indicated by voltmeter or test light, check for an open in IVR, gauge windings, or printed circuit. Do not spark or ground either terminal of IVR, as this could burn out dash wiring or IVR, or both.