Alternator & Regulator Ford Probe I

DESCRIPTION

Alternator has an internal fan and Integrated Circuit (IC) electronic voltage regulator. Internal IC electronic voltage regulator is part of the rotor, brush and brush holder. (Scheme 4) Voltage regulator automatically reduces regulated voltage when ambient temperature increases, so battery charging voltage is maintained at the proper level. Charging system voltage is maintained at an operating range of 14.1-14.7 volts. Alternating current is rectified to direct current by 6 diodes. A check engine warning light is used to indicate charging system malfunction.

Scheme 1

BELT TENSION

Tighten alternator jack screw to achieve belt deflection of 1/4" (6 mm) measured midway between pulleys. Tighten through bolt to 27-38 ft. lbs. (37-52 N.m). Tighten adjusting bracket bolt to 13-18 ft. lbs. (18-24 N.m).

BATTERY VOLTAGE TEST

Connect voltmeter negative lead to negative battery post and positive lead to positive battery post. Record battery voltage for comparison with other test results.

Note. Low state of battery charge may be caused by low current output from alternator. This can occur on vehicles operated under frequent stop and start conditions in high temperatures, coupled with high electrical loads. A new pulley and belt kit is available from manufacturer to correct this condition.

AMPERAGE OUTPUT TEST

1. Connect ammeter in series with positive battery cable. Connect voltmeter negative lead to negative battery post and positive lead to positive battery post.
2. Turn on all electrical accessories. Start engine and accelerate to 2500-3000 RPM. If alternator amperage output is 45 amps or more, alternator is functioning properly. If amperage output is less than 45 amps, proceed to VOLTAGE OUTPUT TEST.

VOLTAGE OUTPUT TEST

Note. Battery must be fully charged for following test and alternator wiring plug must remain connected.

1. Perform battery voltage test and amperage output test before proceeding. Turn off all electrical accessories. Connect ammeter in series to positive battery cable. Start engine and accelerate to 2500 RPM.
2. If ammeter reading is less than 5 amps, proceed to Rotor Field Coil Test. If ammeter reading is more than 5 amps, voltage loss in charging circuit is indicated. Check battery, alternator and engine ground cable connections.
3. Connect positive voltmeter lead to terminal "L" on alternator and negative voltmeter lead to alternator rear housing. (Scheme 2)
4. If reading at terminal "L" is less than 14.4 volts at 68°F (20°C), proceed to REGULATOR POWER SOURCE TEST. If reading at terminal "L" is between 14.4-15.0 volts at 68°F (20°C), problem in stator or rectifier is indicated. See appropriate test under BENCH TESTS.

Scheme 2

REGULATOR POWER SOURCE TEST

Note. Alternator wiring plug must be disconnected for the following test.

1. Disconnect alternator wiring plug. Turn ignition switch to "ON" position (engine not running). Connect positive voltmeter lead to alternator wiring plug terminal "S". (Scheme 3) Connect negative voltmeter lead to alternator rear housing.
2. If reading is same as battery voltage, proceed to ROTOR FIELD COIL TEST. If reading is less than battery voltage, problem is indicated between terminal "S" wire and battery.

Scheme 3

ROTOR FIELD COIL TEST

Note. Terminal "F" is internal and can be accessed through hole in rear housing of alternator. Ensure ohmmeter probe does not touch alternator housing while performing the following test.

1. Disconnect negative battery cable at battery. Disconnect alternator output wire at "B+" terminal. (Scheme 3) Disconnect alternator wiring plug. Set ohmmeter in "x1" range. Connect one probe to alternator terminal "L" and other probe to terminal "F".
2. If ohmmeter reading is 3-6 ohms, alternator field is okay. Proceed to "L" TERMINAL VOLTAGE TEST.
3. If reading is less than 3 ohms or more than 6 ohms, problem is indicated in field rotor, slip rings or brushes. Remove alternator for further testing. See appropriate tests under BENCH TESTS.

"L" TERMINAL VOLTAGE TEST

1. If previously disconnected, connect alternator output wire to "B+" terminal at rear alternator housing and negative battery terminal to battery. Disconnect alternator wiring plug if not previously disconnected.
2. With ignition switch in ON position (engine not running), connect positive voltmeter lead to alternator wiring plug "L" terminal and negative voltmeter lead to alternator rear housing. (Scheme 3)
3. If reading is 1-3 volts, problem is indicated in stator or rectifier. Remove alternator for further testing. See appropriate test under BENCH TESTS.
4. If reading is more than 3 volts, problem is indicated in IC regulator. Remove alternator for further testing. See appropriate test under BENCH TESTS.

RECTIFIER TESTING

1. Use ohmmeter to check for continuity between positive diode lead and heat sink on positive diode side. There should be continuity from positive diode lead to heat sink and no continuity in opposite direction. Repeat test for each diode. If meter readings are not as specified, replace rectifier assembly.
2. Repeat test for negative diodes. Check for continuity between negative diode lead and heat sink at negative diode side. There should be continuity from diode lead to heat sink and no continuity in opposite direction. Repeat test for each diode. If continuity is not as specified, replace rectifier assembly.

STATOR WINDINGS GROUNDED TEST

1. Inspect stator laminations closely for signs of overheating. A burnt spot usually indicates shorted stator winding. Remove stator from alternator. Set ohmmeter on "x1000" scale. Connect one ohmmeter probe to one stator lead and other probe to stator laminated core. Ohmmeter reading should be infinity.
2. If meter needle moves, stator winding is shorted to core and must be replaced. Repeat test for each stator lead. Do not touch probes or stator leads, or an incorrect reading will result.

STATOR WINDINGS OPEN TEST

Remove stator from alternator. Set ohmmeter on "x1" scale. Connect one ohmmeter probe to stator lead and other probe to another stator lead. If no meter movement occurs, stator coil is open and must be replaced. Repeat test with other stator leads. Do not touch probes or stator leads, or an incorrect reading will result.

ROTOR OPEN OR SHORT CIRCUIT TEST

1. Remove rotor from alternator. Set ohmmeter on "x1" scale. Connect each probe to one rotor slip ring. Reading should be 2.0-2.6 ohms. Higher reading indicates damaged slip ring solder connection or broken wire.
2. Lower reading indicates shorted wire or slip ring. Replace rotor if damaged. Connect one ohmmeter probe to slip ring and other probe to rotor core.
3. Ohmmeter reading should be infinity. Reading other than infinity indicates rotor is shorted to shaft and must be replaced. Damaged slip ring terminals or solder touching rotor shaft will cause shorted condition.

Scheme 4

TROUBLE SHOOTING

Note. For trouble shooting, see TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL TROUBLE SHOOTING section.

Note. This procedure has been updated per Ford TSB 92-18B-6.

Scheme 5

Scheme 6

1. Disconnect battery negative cable. remove right hand halfshaft. See «AXLE SHAFTS - FRONT»(/ford/probe/i-1988-1992/remont/axle-shafts/#axle-shafts-front) article in DRIVE AXLES section. depress locking tabs to disconnect wiring harness connector from alternator. Remove "B" terminal attaching nut and the "B" terminal connector. (Scheme 5)
2. Loosen alternator adjustment bolt and the through-bolt enough to allow alternator to pivot. (Scheme 6) Remove alternator drive belt.
3. Remove alternator adjustment bracket, lock bolt and through-bolt. While holding alternator to prevent it from falling, remove alternator between the steering gear and the right halfshaft. (Scheme 5)

Scheme 7

Scheme 8

1. Slide alternator between the steering gear and the right halfshaft. Position alternator on bracket. Install and finger-tighten the alternator through-bolt. (Scheme 6)
2. Install alternator drive belt and adjustment bracket. Install alternator adjustment jack screw and lock bolt. Tighten the alternator adjustment jack screw until.24-.31" (6-8 mm) of belt deflection is achieved. (Scheme 8)
3. Tighten the through-bolt to 27-38 Ft. Lbs. (37-52 N.m). Tighten the alternator adjusting bracket bolt to 13-18 Ft. Lbs. (18-25 N.m).

Removal & Installation - 3.0L

1. Disconnect negative battery cable. Remove drive belt. Remove and set windshield washer reservoir aside. Remove hoses from power steering pump. Plug openings.
2. Remove upper and center accessory bracket mounting bolts. Pull idler tensioner back. Remove lower accessory bracket mounting bolt. Remove accessory bracket mounting bolt at A/C compressor brace.
3. Lift accessory bracket together with alternator. Remove wiring from alternator. Remove alternator pivot and mounting bolts to remove alternator from bracket.
4. To install, reverse removal procedure. Fill and bleed power steering system.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

ALTERNATOR SPECIFICATIONS

ALTERNATOR SPECIFICATIONS (1)

See also:
• TROUBLE SHOOTING - BASIC PROCEDURES
• AXLE SHAFTS - FRONT