1998 Ford Ranger


joe marshall

September, 4, 2010 AT 11:34 AM

Electrical problem
1998 Ford Ranger 4 cyl Two Wheel Drive Manual 150, xx miles

I have replaced my battery, alternator, cable from alt. To fuse, fuse, ignition switch, and my truck still will not charge the battery. The cables are tight, the fan belt is good. I went through a spell where the system would charge every other time I drove it, but iI could never tell what I did or didnt do. I did a continuity test on the battery cables and they were good. What should I check next?


My Alternator Quit Charging


Charging System Trouble


2 Answers



September, 4, 2010 AT 11:59 AM

With the key on you should have power to the yellow and white wire to the alternator and the B+ terminal of the alternator.Do you have power to those two wire's going to the alternator?



September, 4, 2010 AT 12:09 PM

LOW OR NO CHARGE CONDITION 1. Unplug harness connector from regulator at rear of generator. Connect ohmmeter between regulator "A" and "F" terminal screws. See Fig. 1 and Fig. 3 . If resistance is not greater than 2.4 ohms, a short in field circuit or a grounded rotor coil is indicated. Replace generator. If resistance is greater than 2.4 ohms, go to next step. 2. Reconnect regulator wiring plug. Connect negative voltmeter lead to ground. Contact positive voltmeter lead to regulator "A" terminal screw. If voltmeter does not indicate battery voltage, repair open or high resistance in "A" circuit wiring. Perform load test after repairs. 3. If battery voltage is indicated at "A" terminal screw, ensure ignition switch is in OFF position. Connect positive voltmeter lead to regulator "F" terminal screw. If battery voltage is present, go to step 4). If battery voltage is not present, replace generator. 4. Turn ignition switch to ON position (engine off). With voltmeter negative lead to ground, contact positive lead of voltmeter to regulator "F" terminal screw. If voltmeter indicates 2 volts or less, go to next step. If voltage is greater than 2 volts, check circuit between "I" terminal and ignition switch. Repair if necessary. See "S" & "I" CIRCUIT TEST . If "I" circuit is okay, replace regulator. Perform LOAD TEST after repair. 5. Start engine and run at 2000 RPM with headlights on. Measure voltage at "B+" terminal of generator and at generator feed wire at starter relay. If voltage readings differ by more than 0.5 volt, repair high resistance or open in wire between "B+" terminal and junction near starter relay. 6. If generator still does not charge sufficiently, connect a jumper wire to regulator "F" terminal screw and ground it to rear housing. If output voltage increases to 13-15 volts, replace regulator. If output voltage does not increase to at least 13 volts, replace generator. "S" & "I" CIRCUIT TEST 1. Unplug regulator 3-wire harness connector. Connect jumper wire from harness "A" terminal to regulator "A" terminal. See Fig. 1 and Fig. 2 . Connect another jumper wire from regulator "F" terminal screw to generator housing. 2. With engine idling, connect voltmeter negative lead to battery ground terminal. Connect voltmeter positive lead first to "S" terminal and then to "I" terminal of regulator harness connector. See Fig. 2 . Voltage at "S" terminal should be about 7 volts and about 14 volts at "I" terminal. If "S" terminal and "I" voltages are okay, replace voltage regulator. Repeat LOAD TEST. If "S" and "I" circuit voltages are not as specified, go to next step. 3. If voltage is present at "S" terminal, but not 6-8 volts, replace generator. If no voltage is present at "S" terminal, disconnect one-wire connector ("S" terminal) on back of generator. Check voltage at single "S" terminal. If about 7 volts are present, repair "S" circuit wiring. If no voltage is present at single "S" terminal, replace generator. 4. If no voltage is present at "I" terminal, repair indicator light wiring circuit. Restore wiring connections and repeat LOAD TEST.
GENERAL INSPECTION Ensure battery posts and cables are clean and tight. Check drive belt tension. Ensure connections at generator, regulator and engine ground are clean and tight. Check fuses and fusible links, replace as necessary. Check condition of battery to see if battery has the ability to accept and hold a charge. If battery capacity meets requirements, charge battery before proceeding with testing to ensure battery is fully charged. NO-LOAD TEST 1. Connect voltmeter positive lead to B+ terminal on generator and negative lead to ground. Start and run engine at 1500 RPM with no electrical load (foot off brake and doors closed). Read voltmeter when voltage stabilizes. This may require waiting a few minutes. Voltage should be 13-15 volts. 2. If voltage increases to proper level, proceed to LOAD TEST. If voltage increases beyond proper level, proceed to OVERCHARGE CONDITION. If there is no voltage increase, proceed to LOW OR NO CHARGE CONDITION. Fig. 1: Identifying Generator-Regulator Terminals Courtesy of FORD MOTOR COMPANY LOAD TEST 1. Ensure drive belt is in good condition and properly tightened. Connect charging system load tester in accordance with manufacturer's instructions. Start and run engine at 2000 RPM and apply load until generator output amperage levels off. 2. Record maximum generator amperage output. See GENERATOR OUTPUT SPECIFICATIONS table for output values. If generator output is within 20 percent of rated output amperage and voltage remains at 12.5-14.5 volts, generator output is okay. If generator does not produce rated output, proceed with appropriate testing.

Check fuses, ground wires and fusible links at starter solenoid.

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