Battery Source Test
- Without disconnecting coil, connect voltmeter between coil "BAT" terminal (Red wire) and engine ground. Connect a jumper wire from coil "DEC" terminal (Green wire) to a good ground.
- Turn all lights and accessories off and turn ignition on. A reading of 4.9-7.9 volts indicates primary circuit from battery to coil is satisfactory.
Courtesy of FORD MOTOR CO.
- If reading is less than specified, inspect primary wiring for worn insulation, broken strands and loose or corroded terminals. If reading is greater than specified, check and replace resistance wire (if necessary).