Diagnosis & Testing
When operating normally, the generator indicator lamp will come on when the ignition is in RUN position and go out when the engine starts. If the lamp operates abnormally or if an undercharged or overcharged battery condition occurs, the following procedure may be used to diagnose the charging system. Remember that an undercharged battery is often caused by accessories being left on overnight or by a defective switch that allows a lamp, such as a trunk or a glove box lamp, to stay on.
Visually check the belt and the wiring.
- With the ignition in the ON position and the engine stopped, the charge indicator lamp should be on. If not, detach the harness at the generator and ground the -L- terminal in the harness with a 5-ampere jumper lead.
- If the lamp lights, replace the generator. - If the lamp does not light, locate the open circuit between the ignition switch and the harness connector. The indicator lamp bulb may be burned out.
With the ignition switch in the ON position and the engine running at moderate speed, the charge indicator lamp should be off. If not, detach the wiring harness at the generator.
- - If the lamp goes off, replace the generator.
- - If the lamp stays on, check for a short to ground in the harness between the connector and the indicator lamp.
- Replace the generator if it fails that test. If it passes the test, perform the on-vehicle output check which follows.
- Attach a digital multimeter, an ammeter, and a carbon pile load to the vehicle.
- With the ignition switch in the OFF position, check and record the battery voltage.
- Remove the harness connector from the generator.
- Turn the ignition to RUN with the engine not running. Use a digital multimeter to check for voltage in the harness connector -L- terminal.
- The reading should be near the specified battery voltage of 12 volts. If the voltage is too low, check the indicator -L- terminal circuits for open and grounded circuits causing voltage loss. Correct any open wires, terminal connections, etc., as necessary.
- Attach the generator harness connector.
- Run the engine at a moderate idle, and measure the voltage across the battery terminals. The reading should be above that recorded in step 14, but less than 16 volts. If the reading is over 16 volts or below the previous reading, replace the generator.
- Run the engine at a moderate idle, and measure the generator amperage output.
- Turn on the carbon pile, and adjust it to obtain the maximum amps while maintaining the battery voltage above 13 volts.
- If the reading is within 15 amps of the generator-s rating noted on the generator, the generator is good. If not, replace the generator.
- With the generator operating at the maximum output, measure the voltage between the generator housing and the battery negative terminal. The voltage drop should be 0.5 volt or less. If the voltage drop is more than 0.5 volt, check the ground path from the generator housing to the negative battery cable.
- Check, clean, tighten, and recheck all of the ground connections.
Removal & Installation
- Before servicing the vehicle, refer to the Precautions Section.
- Disconnect the negative battery cable.
- Disconnect the manifold air temperature (MAT) sensor electrical connector and remove the air intake tube.
- Remove all clamps from the air cleaner outlet hose, and set aside the tube.
- Raise and safely support the front of the vehicle.
- Disconnect the harness connector from the back of the alternator, and the alternator lead to the battery.
- Remove the serpentine drive belt by lowering the vehicle and turning the automatic tensioner roller bolt clockwise to relieve tension on the belt.
- Push up the power steering reservoir and set it aside.
- Remove the alternator upper mounting bolts to the intake manifold/cylinder head support bracket, the intake manifold strap bracket, and the intake manifold-to-cylinder body strap bracket.
- Raise and suitably support the vehicle and remove the nut and washers which hold the alternator lower bracket-to-alternator bolt. Work the bolt loose and remove the alternator.
- Remove the alternator lower support bracket bolts.
- Carefully remove the alternator with the lower bracket.
- Remove the alternator lower support bracket nut, the bolt, and the washer.
- Install the alternator to the alternator lower bracket and insert the alternator bolt. Tighten the alternator lower bracket-to-alternator nut to 18 ft. lbs. (25 Nm).
- Install the alternator and the lower support bracket assembly to the engine block. Tighten the alternator and the lower bracket-to-engine block bolts to 27 ft. lbs. (37 Nm).
- Install the alternator-to-intake manifold and cylinder head support bracket bolts, the alternator-to-intake manifold strap bracket bolt, and the intake manifold-to-cylinder body strap bracket bolts over the starter.
- Tighten the alternator-to-intake manifold and cylinder head support bracket bolts to 27 ft. lbs. (37 Nm). Tighten the alternator-to-intake manifold strap bracket bolt and the intake manifold-to-cylinder body strap bracket bolts to 16 ft. lbs. (22 Nm).
- Route the serpentine accessory drive belt.
- Relieve tension on the belt by first applying downward pressure on the automatic tension roller bolt and releasing pressure once the belt is in place.
- Install the power steering reservoir.
- Install the air cleaner outlet hose and connect the MAT electrical connector.
- Connect the negative battery cable.