Test 22 - Radiator Fan Relay Circuit Check

Connect diagnostic readout box to engine harness connector. With carburetor switch open, turn ignition switch to "RUN" position. Place Read/Hold switch in the "Hold" position. Code 55 should be displayed on readout box. Connect voltmeter to terminal No. 2 of radiator fan relay and ground. Press and hold the ATM button until Test Code 96 appears on display.
CAUTION: Radiator cooling fan may cycle on and off in this test mode.
Voltmeter reading should be pulsating and relay should be clicking. If voltmeter pulsates and relay clicks, check for poor connection in the circuit. If voltmeter is not pulsating but reads within one volt of battery voltage, proceed to step 3). If voltmeter is not pulsating but reads 0-1 volt, disconnect computer 10-pin connector. If voltage is now within one volt of battery voltage, replace the computer. If not within one volt of battery voltage, proceed to step 5).
Turn the ignition off. Disconnect the computer 10-pin connector. Connect a voltmeter to cavity No. 8 of the 10-pin connector and ground. Turn ignition switch to the "RUN" position.
Voltmeter should read within one volt of battery voltage. If voltage is okay, ensure the terminal in connector cavity No. 8 is not spread apart causing a poor connection. If connection is okay, replace computer. If voltage is not okay, repair wire to cavity No. 8 for an open circuit to radiator fan relay.
Turn the ignition off. Disconnect the smaller of the two 3-pin connectors from the radiator fan relay. Connect an ohmmeter between terminals No. 1 and 2 of the radiator fan relay. Ohmmeter should show resistance.
If there is resistance, turn the ignition switch to the "RUN" position. Check for battery voltage at wire that connects to terminal No. 1 of relay. If there is voltage, repair wire to cavity No. 8 of the computer 10-pin connector for a short to ground. If there is no voltage, repair wire for open circuit to fuse No. 2. If there is an open circuit, replace radiator fan relay.