Alternator - Models W/external Regulator Ford Econoline E350

DESCRIPTION

Note. Unless otherwise specified, references to Pickup include the F350 Super Duty commercial chassis.

Major components of the alternator are a rotor, stator, rectifier assembly and end housings. An external regulator controls alternator output. (Scheme 1)& 2.

Scheme 1

Scheme 2

BELT TENSION

Check condition and tension of alternator drive belt prior to performing any on-vehicle charging system tests. Replace belt and/or repair tensioner mechanism if necessary. On vehicles with automatic belt tensioner, belt tension is okay if belt length indicator is within limit marks on tensioner. On vehicles without automatic belt tensioner, adjust alternator drive belt tension to 160-200 lbs. (73-91 kg) for new belt, or 110-130 lbs. (50-59 kg) for a belt that has been in operation longer than 5 minutes.

TROUBLE SHOOTING

Note. See TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL TROUBLE SHOOTING section.

Scheme 3

Scheme 4

1. Check condition of fuse link, battery terminals, battery cables, connections and belt tension. Make any required corrections. Ensure battery is in good condition and is fully charged.
2. Connect voltmeter to battery posts. Record voltmeter indication as base voltage. Start engine and operate at 1500 RPM with no electrical load. Read voltmeter when voltage stabilizes. If there is no voltage increase, or voltage increase is less than.5 volt over base voltage, go to step 4). If voltage increase is no greater than 2.0 volts, go to next step. If voltage increase is greater than 2.0 volts, go to step 12).
3. Load alternator by switching heater/air conditioner blower motor to high speed and headlights to high beam. Increase engine speed to 2000 RPM. Voltmeter should indicate at least.5 volt higher than base voltage. If voltage increase is within specification, alternator operation is normal. If voltage increase is less than.5 volt higher than base voltage, go to next step.
4. Unplug connector from voltage regulator. Measure resistance between harness connector "F" terminal and ground. If resistance is greater than 3 ohms, go to next step. If resistance is less than 3 ohms, check for grounded field wire to alternator or for shorted alternator field. See «BENCH TESTING»(/ford/econoline-e350/1985-1999/remont/charging-system/#alternator-models-wexternal-regulator).
5. Connect jumper wire between "A" and "F" terminals at harness connector. (Scheme 3) Increase engine speed to 2000 RPM. If voltage increase is less than.5 volt, go to next step. If voltage increase is greater than.5 volt (vehicles with warning light), go to step 8). If voltage increase is greater than.5 volt (vehicles with ammeter), go to step 9).
6. Remove jumper wire from regulator connector. Connect fused jumper wire between alternator BAT and FLD terminals. (Scheme 4) Increase engine speed to 2000 RPM. If voltage increase is less than.5 volt, go to next step. If voltage increase is greater than.5 volt, repair defective "A" or "F" circuit wiring.
7. Stop engine. Measure voltage at alternator BAT terminal. If voltage is equal to base voltage, service alternator. If voltage is not equal to base voltage, repair circuit between alternator and battery.
8. Turn off all loads. Turn ignition off. Connect jumper between "A" and "F" terminals at voltage regulator harness. Start and idle engine. If voltage at regulator harness connector "S" terminal is not approximately 1/2 base voltage, go to step 10). If voltage is approximately 1/2 base voltage, replace voltage regulator. If voltage at "I" terminal is not approximately battery voltage, repair defective "I" circuit between indicator light and alternator.
9. Turn off all loads. With ignition on, but engine not running, measure voltage at "I" terminal at regulator harness connector. If voltage is approximately battery voltage, replace voltage regulator. If voltage is not approximately battery voltage, repair defective "I" circuitry.
10. With engine idling, measure voltage at voltage regulator harness connector "S" terminal. If voltage is approximately 1/2 base voltage, replace voltage regulator. If voltage is approximately zero, go to next step.
11. With engine idling, measure voltage at alternator "S" terminal. If voltage is approximately 1/2 base voltage, repair wire between alternator "S" terminal and voltage regulator harness connector. If voltage is not approximately 1/2 base voltage, service alternator.
12. Connect jumper wire between regulator base and alternator frame. If overvoltage condition still exists, go to next step. If overvoltage condition is eliminated, repair voltage regulator ground.
13. Unplug regulator harness connector. If condition is corrected, replace regulator. If overvoltage condition is still present with regulator disconnected, repair short in wiring harness between alternator and regulator ("A" and "F" circuits).

STATOR GROUND TEST

1. Remove stator from alternator. Set ohmmeter to X1000 scale. Connect one ohmmeter probe to any stator lead. Connect other probe to stator core. Ohmmeter indication should be infinity.
2. If meter indicates continuity, stator winding is shorted to core, and must be replaced. Repeat test for each stator lead. DO NOT touch probes or stator leads, as an incorrect reading will result.

STATOR CONTINUITY TEST

Note. On alternators with delta stators, a single open phase CANNOT be detected by testing with ohmmeter. Delta stators have 2 wires at each terminal.

Disconnect stator from rectifier assembly. Set ohmmeter to X1 range. Connect one ohmmeter probe to any stator lead. Connect other ohmmeter probe to another stator lead. If no continuity exists, stator is open, and must be replaced. Repeat test for each pair of stator leads.

ROTOR TEST

1. Remove rotor from alternator. Set ohmmeter to X1 scale. Measure resistance between rotor slip ring. Resistance should be 2.0-3.5 ohms. Replace rotor if resistance is not within specification.
2. Set ohmmeter to X1000 scale. Connect one ohmmeter probe to either slip ring. Connect other probe to rotor shaft. Resistance other than infinity indicates rotor is shorted to shaft and must be replaced. Damaged slip ring terminals or solder touching rotor shaft can cause shorted condition.

Note. Following test requires use of analog ohmmeter.

DIODE TEST

1. Remove rectifier assembly from alternator. Set ohmmeter to X1 scale. Connect one ohmmeter probe to either terminal screw. Connect other probe to each diode lead terminal in turn. Record resistance measurements.
2. Transpose probes and repeat test. All diodes should have resistance of approximately 6-10 ohms in one direction and no needle movement with probes transposed. Repeat test for other set of diodes, moving first probe to other terminal screw. If measurements are not as specified, replace rectifier assembly.

REMOVAL & INSTALLATION

Disconnect battery negative cable. Disconnect wiring from alternator. Disengage drive belt from alternator pulley. Remove attachment bolts and alternator. Reverse removal procedure to install.

OVERHAUL

Note. For exploded view of alternator (Scheme 5)

Scheme 5

See also:
• TROUBLE SHOOTING - BASIC PROCEDURES
• COMPUTER RELEARN PROCEDURES
• BENCH TESTING