Sensor & Control Unit Test

Fig. 1 Schematic view of American Motors solid state ignition system less electronic feedback system:

Fig. 2 Schematic view of American Motors solid state ignition system with electronic feedback system:

1. Disconnect the four wire connector at the control unit, Figs. 1 and 2. Disconnect coil wire from center tower of distributor and hold wire approximately 1/2 inch from a good engine ground with insulated pliers, then turn ignition "On." If spark is observed at coil wire, proceed to next step. If not, proceed to Step 5.
2. Measure resistance between terminals "D2" and "D3" of the harness connector, Figs. 1 and 2. If resistance is 400-800 ohms, proceed to Step 6. If not, proceed to next step.
3. Disconnect and connect the three wire connector at distributor and measure resistance between terminals "D2" and "D3" of the harness connector, Figs. 1 and 2. If resistance is now between 400-800 ohms, proceed to Step 6. If not, disconnect three wire connector at distributor and proceed to next step.
4. Measure resistance between terminals "B2" and "B3" of the distributor connector, Figs. 1 and 2. If resistance is not 400-800 ohms, repair or replace harness between three wire and four wire connector.
5. Connect an ohmmeter between terminal "D1" of the harness connector, Figs. 1 and 2, and battery negative terminal. If reading is below .002ohm, repeat Step 2. If not, check for an improper ground. Check ground cable resistance, distributor to engine block resistance and distributor ground screw to terminal "D1" resistance, Figs. 1 and 2.
6. Using a voltmeter connected between terminals "D2" and "D3" of the harness connector, Figs. 1 and 2, observe reading while cranking engine. If voltmeter reading fluctuates, it indicates proper sensor and trigger wheel operation. If not, the trigger wheel is defective or the distributor is not rotating.