Field Circuit Test
- If field circuit is grounded and jumper wire is used as a check at regulator wiring plug from "A" to "F" terminals, excessive current will cause heat damage to regulator wiring plug terminals, and may burn jumper wire. If field circuit was grounded, connector wire inside regulator will also be burned open and will result in an under-voltage condition.
- Field cir***uit should be checked with regulator wiring plug disconnected and suitable ohmmeter connected from "F" terminal of regulator wiring plug to battery ground. Ohmmeter should indicate between 4 and 250 ohms.
- Check for regulator burned-open wire is made by connecting an ohmmeter from "1" to "F" terminals on regulator. If reading indicates approximately 10 ohms, connector wire inside regulator is burned open. Field circuit ground condition must be found and repaired before installing new regulator.
- If field circuit is satisfactory, disconnect regulator wiring plug at regulator and connect jumper wire between "A" and "F" terminals on regulator wiring plug. Repeat voltmeter test procedures. If problem of under-voltage still exists, remove jumper wire at regulator plug and leave plug disconnected from regulator, connect jumper wire to "FLD" and "BAT" terminals on alternator. Repeat voltmeter test procedures. If results are now satisfactory, repair wiring harness from alternator to regulator. If voltmeter tests still indicate under-voltage, repair or replace alternator.
Courtesy of FORD MOTOR CO.