Toyota Tercel 1984-1994 Repair Guide

Alternator

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ALTERNATOR PRECAUTIONS



Several precautions must be observed with alternator to avoid damaging the unit:



If the battery is removed or disconnected for any reason, make sure that it is reconnected with the correct polarity. Reversing the battery connections will result in serious damage.
 
When utilizing a booster battery as a starting aid, always connect it as follows: positive-to-positive, and negative (booster battery) to a good ground on the engine of the car being started.
 
Never use a fast charger as a booster to start a car with an alternator.
 
When servicing the battery with a fast charger, always disconnect the car battery cables.
 
Never attempt to polarize an alternator.
 
Never apply more than 12 volts when attempting to jump start the vehicle.
 
Do not use test lamps of more than 12 volts (V) for checking diode continuity.
 
Do not short across or ground any of the terminals on the alternator.
 
Never disconnect the alternator or the battery with the engine running.
 
Always disconnect the battery terminals when performing any service on the electrical system.
 
Disconnect the battery ground cable if arc welding (such as body repair) is to be done on any part of the car.
 

Noise from an alternator may be caused by a loose drive pulley, a loose belt, loose mounting bolts, worn or dirty bearings or worn internal parts. A high frequency whine that is heard at high engine speed or full alternator output is acceptable and should not be considered a sign of alternator failure.

TESTING



See Figures 1, 2 and 3

There are several tests that can be done with inexpensive equipment. The first thing to do is to see if the discharge warning lamp on the dashboard illuminates when the ignition switch is turned ON . If it does not, check for blown fuses, a burned out bulb, or bad connections.

If the warning lamp does light with the ignition switch ON , but stays on with the engine running, check for the following:



Proper electrolyte level (specific gravity) in the battery
 
Loose or missing alternator belt
 
Loose or corroded battery cable
 
A blown fuse or fusible link
 
A shorted or open wire
 

If everything checks out OK, but the charge lamp is still on, the alternator itself is probably to blame. This does not mean the entire alternator needs to be replaced. Many times the voltage regulator may be faulty and cause a no charge condition. Check the alternator and regulator operation by performing the following tests.



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Fig. Fig. 1: Connect a voltmeter and ammeter to the charging circuit as shown



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Fig. Fig. 2: The voltage regulator on models without the IC regulator is adjustable

If a battery/alternator tester is available, connect the tester to the charging circuit as per manufacturer's instructions.

  1. Connect a voltmeter and ammeter to the charging circuit as follows:
    1. Disconnect the wire from terminal B of the alternator and connect it to the negative probe of the ammeter.
    2.  
    3. Connect the test probe from the positive ( + ) terminal of the ammeter to terminal B of the alternator.
    4.  
    5. Connect the positive ( + ) probe of the voltmeter to terminal B of the alternator.
    6.  
    7. Ground the negative (-) probe of the voltmeter.
    8.  

  2.  


CAUTION
Keep all wires, tools, etc., away from moving engine parts. Serious personal injury and damage to the car will result otherwise.

  1. With the engine running from idle to 2,000 rpm, check the reading on the ammeter and voltmeter. Note that the following readings are taken at an ambient temperature of 77° F (25°C). Voltage will decrease slightly as temperature increases.
  2.  



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Fig. Fig. 3: Grounding Terminal F on models with the IC regulator

Amperage:


Less than 10 amps on all models and years
 

Voltage:


13.8-14.8 V on 1984-1986 models without IC regulator
 
13.8-14.4 V on 1984 models with IC regulator
 
13.5-15.1 V on 1985-1987 models with IC regulator
 
13.9-15.1 V on 1988-1994 models with IC regulator
 

  1. On models without the IC regulator, if the voltage reading is not within specifications, adjust or replace the regulator. The regulator can be adjusted by bending the regulator adjusting arm.
  2.  
  3. If the voltage reading is less than specified on models with the IC regulator, proceed as follows:
    1. With terminal F grounded, start the engine and check the voltage reading of terminal B.
    2.  
    3. If the voltage is greater than specified, replace the IC regulator.
    4.  
    5. If the voltage is less than specified, the alternator is probably at fault.
    6.  

  4.  
  5. Remove the ground from terminal F, if applicable.
  6.  
  7. To check the charging system under a load:
    1. With the engine running at 2,000 rpm, turn on the high beams and place the heater fan control switch on HI.
    2.  
    3. Check the amperage reading on the ammeter. It should read 30 amps or more.
    4.  
    5. If the reading is less than 30 amps, the alternator is faulty.
    6.  

  8.  

With the battery fully charged, the reading may sometimes be less than 30 amps.

REMOVAL & INSTALLATION



See Figures 4, 5, 6 and 7


CAUTION
On models equipped with a Supplemental Restraint System (SRS) or "air bag,'' work must NOT be started until at least 90 seconds have passed from the time that both the ignition switch is turned to the LOCK position and the negative cable is disconnected from the battery.

  1. Disconnect the negative battery cable.
  2.  

Failure to disconnect the battery can cause personal injury and damage to the car. If a tool is accidentally shorted at the alternator, it will become hot enough to cause a serious burn. On some models, the alternator is mounted very low on the engine. It may be necessary to remove the gravel shield and work from underneath the car in order to gain access to the alternator retaining bolts.

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