Alternator & Regulator Buick Century V

DESCRIPTION & OPERATION

MODEL IDENTIFICATION

BODY CODE

Charging System (CS) series alternators include a delta stator, rectifier bridge, and rotor with slip rings and brushes. A built-in regulator incorporates fault detection circuitry. A conventional pulley and external fan are used to cool slip ring end frame, rectifier bridge and regulator. On some models the external fan has been replaced with a Dual Internal Fan (DIF). The DIF is located inside alternator and draws air into and through alternator housing to provide cooling of internal components.

Most CS series alternators operate with 2 wire connections and a ground path through the mounting bracket. The first wire connection is the BAT (output) terminal. This terminal must be connected to the battery during operation. The second wire connection is through the charge indicator light or an external resistor to terminal "L" of the regulator. This connection provides initial excitation at start-up.

Three other regulator terminals, "P", "F/I" and "S", are provided for optional use. Terminal "P" is connected to the stator and may be connected to a tachometer. Terminal "F/I" provides an alternative method for turning on the alternator without going through the indicator light or external resistor. Terminal "S" may be used to sense electrical system voltage at a remote point on the vehicle. If terminal "S" is not used, the regulator senses internal alternator voltage.

Some CS144 models have 3 auxiliary phase terminals which supply current to operate heated windshields if equipped.

No periodic maintenance is necessary. CS144 alternators, except for those with 3 auxiliary phase terminals, can be disassembled and repaired. All CS121, CS130, and CS144 alternators with 3 auxiliary phase terminals, are serviced by replacement only.

Regulated voltage varies with temperature. System limits voltage by controlling rotor field current while field current is on. Regulator switches rotor field current on and off at a fixed frequency of 400 cycles per second to help control radio noise. By varying overall on/off time, correct average field current for proper system voltage control is obtained. At high speeds, with lower electrical loads, on-time may be 10 percent of off-time. At low speeds, with higher electrical loads, on-time may be 90 percent of off-time. See the ALTERNATOR USAGE/AMP OUTPUT RATING table.

ADJUSTMENTS

Note. No adjustment or maintenance is required on alternator assembly. Regulator voltage is preset and no adjustment is possible. Drive belt tension is controlled by a belt tensioner.

TROUBLE SHOOTING

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

ON-VEHICLE TESTING

Note. Alternators on "E" and "K" bodies are controlled by Powertrain Control Module (PCM) or Instrument Panel Cluster (IPC). For system and related trouble code diagnosis, see appropriate ALTERNATOR article in this section. Refer to the following list.

1. Concours, Eldorado, & Seville, see: «ALTERNATOR - 4.6L»(ref-58457)
2. DeVille 4.6L, see: «ALTERNATOR - 4.6L»(ref-58457)
3. DeVille 4.9L, see: «ALTERNATOR - 4.9L»(ref-58462)

Note. Only CS144 alternators without auxiliary phase terminals are repairable. CS121 and CS130 alternators are serviced as a complete assembly.

CHARGING SYSTEM WITH CHARGE LIGHT

1. Ensure battery is fully charged. Visually check alternator belt and wiring. Turn ignition switch to ON position (engine not running). Charge light should come on. If light does not come on, go to step 2). If light comes on, go to step 4).
2. Turn ignition off. Disconnect harness alternator connector. Using a fused (5-amp) jumper wire, connect terminal "L" of alternator harness connector to ground. Turn ignition on. If light illuminates, repair wiring connections or replace or repair alternator. See «WIRING DIAGRAMS»(/buick/century/v-1982-1996/remont/charging-system/#alternator-regulator) .
3. If light still does not come on, check charge light bulb and circuit between alternator terminal "L" and ignition switch for an open.
4. Start engine and run at 1500 RPM. Charge light should be off. If charge light stays on, turn ignition off. Disconnect alternator wiring harness connector. Start engine and slowly increase to 1500 RPM. If light does not come on, replace alternator. If light stays on, check for short to ground in alternator terminal "L" circuit harness connector and charge indicator light.

CHARGING SYSTEM WITH GAUGES

1. Visually check alternator belt and wiring. With ignition off, disconnect harness connector at alternator. Turn ignition on. Connect negative lead of a voltmeter to a good engine ground. Connect positive voltmeter lead, in turn, to terminals "F" or "I" and "L" of alternator harness connector. See «WIRING DIAGRAMS»(/buick/century/v-1982-1996/remont/charging-system/#alternator-regulator) .
2. If battery voltage is not present, repair open circuit between alternator connector terminal and battery. If battery voltage is present, connect the harness connector, and proceed to the «UNDERCHARGED OR OVERCHARGED BATTERY»(/buick/century/v-1982-1996/remont/charging-system/#alternator-regulator__undercharged-or-overcharged-battery) test.

UNDERCHARGED OR OVERCHARGED BATTERY

Note. Ensure battery is fully charged and in good condition before performing the following steps. If battery is not at (or near) a fully charged condition, or if its condition is questionable, substitute a known good battery before proceeding.

1. Turn ignition and all accessories off. Measure battery voltage and record for use in step 2). Disconnect alternator connector. Turn ignition on. Using a DVOM, connect positive voltmeter lead to alternator terminal "L" and negative lead to ground. On vehicles with gauges, also connect DVOM to alternator terminals "F" or "I". See «WIRING DIAGRAMS»(/buick/century/v-1982-1996/remont/charging-system/#alternator-regulator) . If battery voltage is present at terminal(s), turn ignition off, connect alternator harness connector and go to next step. If battery voltage is not present, check and repair open in circuit between alternator terminal(s) and battery. CAUTION: Carbon pile testing is part of this procedure. To avoid battery explosion, turn carbon pile OFF before connecting to or disconnecting from vehicle battery.
2. Disconnect negative battery cable. Connect ammeter to alternator output (BAT) terminal. Connect negative battery cable. With load off, connect carbon pile load tester across battery terminals. Start engine and slowly increase to approximately 1500 RPM. Measure voltage between battery terminals. If voltage is between 16 volts and battery voltage measured in step 1), go to step 4). If voltage is not between 16 volts and battery voltage, go to next step.
3. If voltage is greater than 16 volts, check alternator terminal "S" circuit, if used, for high resistance or a bad connection. Repair circuit and/or bad connection as needed. If circuit is okay or not used and voltage is greater than 16 volts or less than battery voltage measured in step 1), replace alternator.
4. With engine at approximately 1500 RPM, turn accessories on and load battery with carbon pile load until maximum alternator output is reached. Adjust the carbon pile to maintain 13 volts or more. Measure the amperage output. If amperage output is within 15 amps of rated output, alternator is okay. If amperage output is not within 15 amps of rated output, repair or replace the alternator. Refer to the «ALTERNATOR USAGE/AMP OUTPUT RATING»(/buick/century/v-1982-1996/remont/charging-system/#alternator-regulator) table.

ALTERNATOR OUTPUT TEST

Note. Bench test can be used to verify operation of CS144 alternator after repairs.

Scheme 1

1. Mount alternator on test stand. Set test stand controls to turn alternator clockwise. Ensure ground polarity of alternator and battery are the same. Ensure battery is fully charged. Connect voltmeter, ammeter and carbon pile (in the OFF position). Connect a 30-500 ohm resistor between battery and terminal "L" of alternator. (Scheme 1)
2. Slowly increase alternator speed while observing voltmeter. If output is uncontrolled and increases to greater than 16 volts, rotor field coil is shorted and/or regulator is defective. A shorted rotor field coil can cause regulator failure.
3. If voltage is less than 16 volts, increase speed and adjust carbon pile to obtain maximum output current. Maintain voltage greater than 13 volts. If output is within 15 amps of rated output, alternator is okay. If output is not within 15 amps of rated output, replace alternator. See «ALTERNATOR USAGE/AMP OUTPUT RATING»(/buick/century/v-1982-1996/remont/charging-system/#alternator-regulator) table.

ROTOR TEST

Note. Install new bearing at slip ring end whenever alternator is reassembled. When disassembling alternator, carefully note locations of insulated and uninsulated screws.

CS144 (Without Auxiliary Phase Terminals)

1. Scribe end frames to facilitate reassembly. Remove through-bolts and separate end frames.
2. With ohmmeter set to its lowest range, measure coil resistance between slip rings. (Scheme 2) Replace rotor if coil resistance is not 2.1-2.4 ohms at 70°F (21°C).
3. With ohmmeter set to its highest range, check for grounds between either slip ring and rotor pole piece. (Scheme 2) If reading is not close to infinite, replace rotor.
4. To reassemble alternator, reverse disassembly procedure. Retain brushes with brush retaining pin during reassembly. (Scheme 3) Remove retaining pin after tightening through-bolts.

Scheme 2

Scheme 3

STATOR TEST

Note. Install new bearing at slip ring end whenever alternator is reassembled.

1. Scribe end frames to facilitate reassembly. Remove through-bolts and separate end frames. Remove stator lead attaching nuts and remove stator.
2. With ohmmeter set to its highest range, ensure coil is not grounded to stator core. (Scheme 4) Ohmmeter should indicate infinite resistance. If ohmmeter does not indicate infinity, replace stator. Stator cannot be checked for opens or shorts with ohmmeter.
3. To reassemble alternator, reverse disassembly procedure. Retain brushes with brush retaining pin during reassembly. (Scheme 3) Remove retaining pin after tightening through-bolts.

Scheme 4

RECTIFIER BRIDGE TEST

Note. Install new bearing at slip ring end whenever alternator is reassembled.

Scheme 5

1. Scribe end frames to facilitate reassembly. Remove through-bolts and separate end frames. Remove stator. Connect ohmmeter between grounded heat sink and any of 3 grounded flat metal rectifier bridge terminal connectors and note reading. (Scheme 5)
2. Reverse meter leads. If both readings are the same, replace rectifier bridge. Repeat test between grounded heat sink and other 2 flat metal terminal connectors. If readings are the same when leads are reversed at either connection, replace rectifier bridge.
3. Repeat test between insulated heat sink and its 3 flat rectifier bridge metal connectors. Replace rectifier bridge if test readings are the same when leads are reversed at any test connection.
4. To reassemble alternator, reverse disassembly procedure. Retain brushes with brush retaining pin during reassembly. (Scheme 3) Remove retaining pin after tightening through-bolts.

REMOVAL & INSTALLATION

Note. Removal and installation procedures not available for all models.

ALTERNATOR (AUTOMATIC TRANSAXLE - 3.4L)

Removal

1. Remove air cleaner. Disconnect the negative battery cable. Disconnect coolant recovery tank and position aside. Remove the serpentine belt. Raise vehicle and suitably support it.
2. Remove tire and wheel assemblies. Remove right engine splash shield upper retaining clips and pull down shield. Remove front exhaust pipe and converter assembly.
3. Remove steel drive axle shield retaining screws and shield. Remove ball joint nut and separate control arm. Remove right drive axle from transaxle.
4. Remove steering gear heat shield retaining screws and shield. Disconnect knock sensor electrical connector. Remove alternator cooling duct. Remove alternator rear brace bolt. Access bolt through left wheel opening using a 4 foot extension.
5. Loosen alternator rear brace bolt nut at engine. Access nut through right wheel well behind alternator. Remove power steering clip and upper alternator stud nut.
6. Disconnect alternator electrical connectors from alternator. Remove nut and disconnect battery positive lead from alternator output ("BAT") terminal. Remove alternator assembly upper stud and lower bolt/screw. Remove alternator.

Installation

1. Install alternator. Connect alternator electrical connectors to alternator. Connect the battery positive lead and nut to alternator output ("BAT") terminal. Connect alternator to mounting bracket and loosely install mounting bolt. NOTE: If replacement alternator does not fit, remove adhesive- backed shim from alternator bracket.
2. Install alternator rear brace and bolt, including cooling duct bracket. Access bolt through left wheel opening using a 4 foot extension. Tighten alternator lower mounting bolt to 37 ft. lbs. (50 N.m). Tighten alternator upper mounting stud to 18 ft. lbs. (25 N.m). Access the alternator rear brace nut through the right wheel well behind alternator and tighten to 37 ft. lbs. (50 Nm). Tighten alternator rear brace bolt to 18 ft. lbs. (25 N.m).
3. Install upper alternator stud nut and power steering clip. Install alternator cooling duct. Install knock sensor electrical connector.
4. Install steering gear heat shield and retaining screws. Install right drive axle to transaxle. Install right control arm and ball joint. Install steel drive axle shield and retaining screws.
5. Install front exhaust pipe and converter assembly. Install right engine splash shield using upper retaining clips. Install both tire and wheel assemblies. Lower vehicle.
6. Install serpentine belt. Install coolant recovery tank. Connect negative battery cable and tighten cable bolt to 11 ft.lbs. (15 N.m). Install air cleaner assembly.

Note. Adjust transaxle fluid if necessary.

Scheme 6

Remove air cleaner.

1. Disconnect the negative battery cable. Remove the serpentine belt, power steering clip and upper alternator stud nut. Raise vehicle and suitably support.
2. Remove right front tire and wheel assembly. Remove right engine splash shield upper retaining clips and pull down shield. Remove plastic outboard drive axle shield. Remove alternator rear brace retaining bolt and nut.
3. Remove alternator rear brace, including cooling duct bracket. Disconnect alternator electrical connectors from alternator, battery positive lead and nut from alternator output ("BAT") terminal.
4. Remove ball joint nut and separate control arm. Remove right drive axle at transaxle, steel outboard drive axle shield, rear motor mount bracket brace retaining bolts with steel inboard drive axle shield attached. Remove alternator retaining upper stud, lower bolt and alternator.

1. Connect alternator to mounting bracket and loosely install mounting bolt and stud. Tighten alternator lower mounting bolt to 37 ft.lbs. (50 N.m) and upper alternator stud to 18 ft.lbs. (25 N.m). NOTE: If replacement alternator does not fit, remove adhesive- backed shim from alternator bracket.
2. Install rear motor mount bracket brace retaining bolts with steel inboard drive axle shield attached. Install steel outboard drive axle shield, right drive axle at transaxle and ball joint nut.
3. Connect alternator electrical connectors to alternator. Connect battery positive lead and nut to alternator output ("BAT") terminal, tighten nut to 71 inch lbs. (8 N.m). Install alternator rear brace and tighten rear brace bolt to 18 ft.lbs. (25 N.m). and tighten rear brace nut to 37 ft.lbs. (50 N.m) bolt. This includes the cooling duct bracket.
4. Install plastic outboard drive axle shield, right engine splash shield and upper retaining clips, right front tire and wheel assembly. Lower vehicle. Install power steering clip, upper alternator stud nut and serpentine belt. Connect negative battery cable and tighten cable bolt to 11 ft.lbs (15 N.m). Install air cleaner.

Disconnect negative battery cable. Raise vehicle and suitably support. Remove alternator rear brace retaining bolt and nut, including cooling duct bracket. Remove alternator rear brace.

Install alternator rear brace, rear brace retaining bolt and nut, including cooling duct bracket and tighten. Tighten the alternator rear brace bolt to 18 ft.lbs. (25 N.m). Tighten the alternator rear brace nut to 37 ft.lbs. (50 N.m). Lower vehicle and connect negative battery cable.

OVERHAUL

Note. Replacement parts are not available for CS121 and CS130 alternators. If alternator is defective, install a new unit. CS144 alternators without auxiliary terminals for heated windshields may be disassembled for repair.

BRUSHES & REGULATOR

Note. Install new bearing at slip ring end whenever alternator is reassembled.

1. Scribe end frames to facilitate reassembly. Remove through-bolts and separate end frames. Unsolder brush connections. Remove attaching screws and connectors. Remove regulator and brush holder. Clean new brushes with soft dry cloth.
2. Put brushes in holder and hold with brush retaining pin. (Scheme 3) Install brush holder into alternator by reversing removal procedure. To reassemble alternator, reverse disassembly procedure. Remove brush retainer pin after tightening through-bolts.

DRIVE-END BEARING

Note. Install new bearing at slip ring end whenever alternator is reassembled.

1. Scribe end frames to facilitate reassembly. Remove through-bolts and separate end frames. Remove shaft nut while holding rotor with hex wrench inserted into shaft end. Push rotor from housing. Remove retainer plate and press bearing out. On some alternators, drive end bearing cannot be replaced.
2. To install new bearing, press against outer race until bearing seats. Bearing is sealed; no added lubricant is required. Assemble retainer and press rotor into end frame. Tighten shaft nut to 40-80 ft. lbs. (54-108 N.m).
3. To reassemble alternator, reverse disassembly procedure. Retain brushes with brush retaining pin during reassembly. (Scheme 3) Remove retaining pin after tightening through-bolts.

ALTERNATOR SPECIFICATIONS

ALTERNATOR USAGE/AMP OUTPUT RATING

Charging System Schematic ("A" Body). Scheme 7

Charging System Schematic ("B" Body). Scheme 8

Charging System Schematic ("C/H" Body 88 & Ninety-Eight). Scheme 9

Charging System Schematic ("C/H" Body LeSabre & Park Avenue). Scheme 10

Charging System Schematic ("D" Body). Scheme 11

Charging System Schematic ("F" Body). Scheme 12

Charging System Schematic ("H" Body - Bonneville). Scheme 13

Charging System Schematic ("J" Body - Cavalier). Scheme 14

Charging System Schematic ("J" Body - Sunbird). Scheme 15

Charging System Schematic ("L" Body). Scheme 16

Charging System Schematic ("N" Body). Scheme 17

Charging System Schematic ("W" Body - Except Lumina). Scheme 18

Charging System Schematic ("W" Body - Lumina). Scheme 19

Charging System Schematic ("Y" Body). Scheme 20

See also:
• COMPUTER RELEARN PROCEDURES
• TROUBLE SHOOTING - BASIC PROCEDURES
• ALTERNATOR USAGE/AMP OUTPUT RATING
• UNDERCHARGED OR OVERCHARGED BATTERY