Generator & Regulator: Diagnosis Saturn SL II

TROUBLE SHOOTING

Note. See TROUBLE SHOOTING article in GENERAL INFORMATION.

ON-VEHICLE TESTING

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 condition is questionable, substitute a known-good battery before proceeding.

PARASITIC LOAD TEST

Note. Remove ignition key from cylinder before load testing. Key reminder circuit is activated by key cylinder switch when key is in ignition cylinder. This adds 20 milliamps of current draw.

1. Normal parasitic drain should be 8.75-9.5 milliamps. Turn ignition and all accessories off. Disconnect negative battery cable. On all models except coupe with DOHC engine, install an ammeter between negative battery cable and negative battery terminal so that ammeter is in series with other resistances. Read and record parasitic current drain from battery.
2. On coupe with DOHC engine, install a jumper wire between negative battery cable and negative battery terminal. While jumper is installed, connect leads of ammeter to battery cable and negative battery terminal. This puts ammeter in parallel with jumper wire. After 10 seconds, remove jumper wire. Read and record parasitic drain from battery.
3. On all models, start removing fuses to find source of excessive load. If voltage drops across tester when fuse is removed, circuit(s) protected by that fuse is source of current drain. Repair circuit and retest for parasitic drain. For normal parasitic loads, see «NORMAL PARASITIC LOADS»(ref-654-S32272025562000031300000) table.

NORMAL PARASITIC LOADS

BATTERY/GENERATOR LOAD TEST

Note. Following test is for use with electronic system tester (SA9154A).

1. Ensure fusible link between starter and generator is okay. Ensure connections are clean and tight. NOTE: Blown fusible link may be caused by an internal generator failure. Verify no external arcing or shorting of fusible link with other wires and/or components is present. If no problems are found, replace generator and fusible link.
2. Connect large, Red tester cable to battery positive. Connect large, Black tester cable to battery negative. Place Gray inductive current pick-up around battery positive cable. Ensure arrow on Gray inductive pick-up is pointing toward starter motor solenoid. NOTE: Place Gray inductive current pick-up around battery positive cable between battery positive terminal and starter solenoid connection. Easiest place to connect inductive pick-up is next to brake master cylinder. Battery positive cable runs under master cylinder and is covered by a protective wire conduit. This conduit does not need to be removed for this test. On models equipped with Anti-Lock Brake System (ABS), inductive pick-up can be placed between ABS master cylinder and starter motor.
3. Press CHARGING SYSTEM TEST button. Display should show correct number of cylinders. To change number of cylinders, press appropriate number button on keypad.
4. Run engine at 2000 RPM until display flashes MAINTAIN 2000 RPM. Hold engine speed at 2000 RPM until counter counts down from 10 seconds. When 10 seconds are over, run engine at idle until display flashes MAINTAIN IDLE.
5. Hold at idle for a few seconds until display flashes TEST COMPLETE. Turn engine off. Press CONTINUE button to see results of testing. Tester will display voltage and current output of generator.
6. With a good battery in vehicle, voltage output should be 13.0-15.5 volts. All CS series generators should be able to produce within 15 amps of rated output at 2000 RPM.
7. Vehicles are equipped with a 96-amp generator and should have a current output of 16-36 amps at 650 RPM with a generator inlet air temperature of 81-221°F (27-105°C) or an output of 68-95 amps at 2000 RPM with a generator inlet air temperature of 81-221°F (27-105°C). NOTE: Higher inlet temperature results in a reduced amperage output.
8. If generator does not pass voltage and current tests, ensure battery is fully charged and no excessive electrical loads are present. If battery and electrical loads are okay, replace generator.

CARBON PILE LOAD GENERATOR TEST

Note. Ensure battery is fully charged when performing this test.

1. Ensure fusible link between starter and generator is okay. Ensure connections are clean and tight. NOTE: Blown fusible link may be caused by an internal generator failure. Verify no external arcing or shorting of fusible link with other wires and/or components is present. If no problems are found, replace generator and fusible link.
2. Install carbon pile load tester and voltmeter across battery terminals, and connect clamp-on ammeter to one of the battery cables. Start engine and increase engine speed to 2000 RPM.
3. With engine at 2000 RPM, observe voltmeter. If voltage is uncontrolled or is greater than 16 volts, generator is bad. Replace generator. If voltage is less than 16 volts, turn carbon pile load tester on.
4. While maintaining engine speed at 2000 RPM, adjust carbon pile tester to obtain a maximum current reading on ammeter. DO NOT allow voltage to fall to less than 13 volts. If generator output current is within 15 amps of rated output, generator is good.