Charging System — Single Generator [Archive]

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PSDPlayer

07-27-2007, 12:17 PM

Principles of Operation

http://www.gogodiesel.com/forum/filestorage/shopmanual/charging/A0041085.gif

<TABLE cellSpacing=0 cellPadding=3 border=1><CAPTION>Connector C102a End View </CAPTION><TBODY><TR><TH vAlign=bottom align=middle></TH></TR><TR><TD vAlign=top align=middle>A Circuit 35 (OG/LB)</TD></TR><TR><TD vAlign=top align=middle>I Circuit 904 (LG/RD)</TD></TR></TBODY></TABLE>

PSDPlayer

07-27-2007, 12:26 PM

Inspection and Verification

WARNING: Batteries contain sulfuric acid. Avoid contact with skin, eyes, or clothing. Also, shield your eyes when working near batteries to protect against possible splashing of the acid solution. In case of acid contact with skin or eyes, flush immediately with water for a minimum of 15 minutes and get prompt medical attention. If acid is swallowed, call a physician immediately. Failure to follow these instructions may result in personal injury.

WARNING: Batteries normally produce explosive gases which can cause personal injury. Therefore, do not allow flames, sparks or lighted substances to come near the battery. When charging or working near a battery, always shield your face and protect your eyes. Always provide ventilation. Failure to follow these instructions may result in personal injury.

WARNING: When lifting a plastic-cased battery, excessive pressure on the end walls could cause acid to spew through the vent caps resulting in personal injury, damage to the vehicle or to the battery. Lift with a battery carrier or with your hands on opposite corners. Failure to follow these instructions may result in personal injury.

Verify the customer concern by operating the engine to duplicate the concern.
Inspect the charging system (battery, generator cable, harness connectors, connections) to determine if any obvious mechanical or electrical concerns exist. If found, repair as necessary and test the system for normal operation. Refer to the following tables:
<TABLE cellSpacing=0 cellPadding=3 border=1><CAPTION>Visual Inspection Chart </CAPTION><TBODY><TR><TH vAlign=bottom align=middle>Mechanical</TH><TH vAlign=bottom align=middle>Electrical</TH></TR><TR><TD vAlign=top align=left>

Battery case, posts, hold-down clamp, cables and connections for damage
Generator drive (serpentine) belt for condition and tension to make sure there is no slip between the belt and the pulley. For additional information, refer to Section 303-05.
Battery charge
Generator pulley
</TD><TD vAlign=top align=left>

Central junction box (CJB) fuse 45 (10A)
Charging system warning indicator
Circuitry
Cables
</TD></TR></TBODY></TABLE>

Check the operation of the charging system warning indicator (instrument cluster). Normal operation is as follows:
With the ignition switch OFF, the charging system warning indicator should be OFF.
With the ignition switch ON and the engine off, the charging system warning indicator should be on.
With the engine running, the charging system warning indicator should be off.

Verify the battery condition. Refer to Section 414-01.
<TABLE cellSpacing=0 cellPadding=3 border=1><CAPTION>Normal Charging System Voltages and Charging System Warning Indicator Operation </CAPTION><TBODY><TR><TH vAlign=bottom align=middle>Ignition Switch Position</TH><TH vAlign=bottom align=middle>A Circuit 35 (OG/LB)</TH><TH vAlign=bottom align=middle>I Circuit 904 (LG/RD)</TH><TH vAlign=bottom align=middle>Generator B+ Circuit 36 (YE/WH)</TH><TH vAlign=bottom align=middle>Battery</TH><TH vAlign=bottom align=middle>Engine to Battery Ground</TH><TH vAlign=bottom align=middle>Charging System Warning Indicator Operation</TH></TR><TR><TD vAlign=top align=left>OFF</TD><TD vAlign=top align=left>12 volts</TD><TD vAlign=top align=left>0 volts</TD><TD vAlign=top align=left>12 volts</TD><TD vAlign=top align=left>12 volts</TD><TD vAlign=top align=left>0 volts</TD><TD vAlign=top align=left>Off</TD></TR><TR><TD vAlign=top align=left>ON-engine off</TD><TD vAlign=top align=left>12 volts</TD><TD vAlign=top align=left>1-3 volts</TD><TD vAlign=top align=left>12 volts</TD><TD vAlign=top align=left>12 volts</TD><TD vAlign=top align=left>0 volts</TD><TD vAlign=top align=left>Illuminated</TD></TR><TR><TD vAlign=top align=left>ON-engine running</TD><TD vAlign=top align=left>13-
15 volts
</TD><TD vAlign=top align=left>8-9 volts</TD><TD vAlign=top align=left>13-
15 volts
</TD><TD vAlign=top align=left>13-
15 volts
</TD><TD vAlign=top align=left>0 volts</TD><TD vAlign=top align=left>Off</TD></TR></TBODY></TABLE>

If the customer concern is verified after the initial inspection, refer to the Symptom Chart to determine which test(s) to carry out.

PSDPlayer

07-27-2007, 12:30 PM

<TABLE cellSpacing=0 cellPadding=3 rules=groups width="90%" border=1><CAPTION>Symptom Chart</CAPTION><COLGROUP><COLGROUP><COLGROUP><TBODY><TR><TH>Condition</TH><TH>Possible Sources</TH><TH>Action</TH></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>
Battery is discharged or battery voltage is low</TD><TD>
Corroded terminal(s).
Loose connection(s).
High key-off current drain(s).
Battery.
Generator.</TD><TD>
Go To Pinpoint Test A.</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>
The charging system warning indicator is on with the engine running (the charging system voltage does not increase)</TD><TD>
Circuitry.
Voltage regulator.
Generator.</TD><TD>
Go To Pinpoint Test B.</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>
The system overcharges (battery voltage greater than 15.5 volts)</TD><TD>
Circuitry.
Voltage regulator.
Generator.</TD><TD>
Go To Pinpoint Test C.</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>
The charging system warning indicator is on with the engine running and the battery increases voltage</TD><TD>
Circuitry.
Instrument cluster.
Voltage regulator.
Generator.</TD><TD>
Go To Pinpoint Test D.</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>
The charging system warning indicator is off with the ignition switch in the RUN position and the engine off</TD><TD>
Bulb.
Circuitry.
Instrument cluster.
Voltage regulator.
Generator.</TD><TD>
Go To Pinpoint Test E.</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>
The charging system warning indicator flickers or is intermittent</TD><TD>
Corroded terminal(s).
Fuse(s).
Circuitry.
Voltage regulator.
Generator.</TD><TD>
Go To Pinpoint Test F.</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>
The generator is noisy</TD><TD>
Bolts or brackets.
Drive belt.
Generator or pulley.</TD><TD>
Go To Pinpoint Test G.</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>
Radio interference</TD><TD>
Generator.
Circuitry.
In-vehicle entertainment system.</TD><TD>
Go To Pinpoint Test H.</TD></TR></TBODY></TABLE>

PSDPlayer

07-27-2007, 12:33 PM

Pinpoint Tests

CAUTION: Do not make jumper connections except as directed. Incorrect connections may damage the voltage regulator test terminals, fuses, or fuse links.

CAUTION: Do not allow any metal object to come in contact with the generator housing and internal diode cooling fins.
NOTE: All voltage measurements are referenced to the negative (-) battery post unless otherwise specified.

PINPOINT TEST A: BATTERY IS DISCHARGED OR VOLTAGE IS LOW

<TABLE cellSpacing=0 cellPadding=3 width="96%" border=1><TBODY><TR><TH>Test Step</TH><TH>Result / Action to Take</TH></TR><TR><TD>A1 CHECK THE BATTERY CONDITION</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Carry out the Battery — Condition Test to determine if the battery can hold a charge and is OK for use. Refer to Section 414-01.
Is the battery OK?
</TD><TD style="BORDER-TOP: medium none">Yes
GO to A2.

No
INSTALL a new battery. REFER to Section 414-01. TEST the system for normal operation.
</TD></TR><TR><TD>A2 CHECK FOR GENERATOR OUTPUT</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Carry out the On-Vehicle Generator Load/No-Load Tests. Refer to Component Tests in this section.
Is the generator OK?
</TD><TD style="BORDER-TOP: medium none">Yes
GO to A3.

No
GO to Pinpoint Test B.
</TD></TR><TR><TD>A3 CHECK FOR CURRENT DRAINS</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Carry out the Battery — Drain Test. Refer to Component Tests in this section.
Are there any excessive current drains?
</TD><TD style="BORDER-TOP: medium none">Yes
REPAIR as necessary. TEST the system for normal operation.

No
GO to A4.
</TD></TR><TR><TD>A4 CHECK FOR CURRENT DRAINS WHICH SHUT OFF WHEN THE BATTERY IS DISCONNECTED</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Carry out the Battery — Electronic Drains Which Shut Off When the Battery Cable is Disconnected Test. Refer to Component Tests in this section.
Are there any current drains which shut off when the battery is disconnected?
</TD><TD style="BORDER-TOP: medium none">Yes
REPAIR as necessary. TEST the system for normal operation.

No
GO to Pinpoint Test B.
</TD></TR></TBODY></TABLE>
PINPOINT TEST B: THE CHARGING SYSTEM WARNING INDICATOR IS ON WITH THE ENGINE RUNNING (THE CHARGING SYSTEM VOLTAGE DOES NOT INCREASE)

<TABLE cellSpacing=0 cellPadding=3 width="96%" border=1><TBODY><TR><TH>Test Step</TH><TH>Result / Action to Take</TH></TR><TR><TD>B1 CHECK GENERATOR B+ CIRCUIT 36 (YE/WH)</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Measure the voltage between generator B+ terminal, circuit 36 (YE/WH), component side and ground.
http://www.gogodiesel.com/forum/filestorage/shopmanual/charging/A0065976.gif
Is the voltage equal to battery positive voltage (B+)?
</TD><TD style="BORDER-TOP: medium none">Yes
GO to B2.

No
REPAIR the circuit. TEST the system for normal operation.
</TD></TR><TR><TD>B2 CHECK GENERATOR GROUND A CIRCUIT 35 (OG/LB)</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Disconnect: Generator C102a.
Measure the voltage between generator C102a pin A, circuit 35 (OG/LB), harness side and ground.
http://www.gogodiesel.com/forum/filestorage/shopmanual/charging/A0041084.gif
Is the voltage equal to battery positive voltage (B+)?
</TD><TD style="BORDER-TOP: medium none">Yes
GO to B3.

No
REPAIR the circuit. TEST the system for normal operation.
</TD></TR><TR><TD>B3 CHECK I CIRCUIT 904 (LG/RD) FOR AN OPEN</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Disconnect: Generator C102a.
Key in ON position.
With the ignition switch in the ON position and the engine off, measure the voltage between generator C102a pin I, circuit 904 (LG/RD), harness side and ground.
http://www.gogodiesel.com/forum/filestorage/shopmanual/charging/A0041083.gif
Is the voltage equal to battery positive voltage (B+)?
</TD><TD style="BORDER-TOP: medium none">Yes
GO to B4.

No
REPAIR the circuit. TEST the system for normal operation.
</TD></TR><TR><TD>B4 CHECK FOR VOLTAGE DROP IN B+ CIRCUIT 36 (YE/WH)</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Key in START position.
With the engine running, turn the headlamps on, rear defroster on, and the blower motor to the high position.
With the engine at 2,000 rpm, measure the voltage drop between the generator B+ terminal, circuit 36 (YE/WH), component side and the positive battery terminal.
http://www.gogodiesel.com/forum/filestorage/shopmanual/charging/A0065975.gif
Is the voltage drop less than 0.5 volt?
</TD><TD style="BORDER-TOP: medium none">Yes
INSTALL a new generator. REFER to Section 414-02.

No
REPAIR high resistance in the B+ circuit 36 (YE/WH). TEST the system for normal operation.
</TD></TR></TBODY></TABLE>
PINPOINT TEST C: THE SYSTEM OVERCHARGES (BATTERY VOLTAGE IS GREATER THAN 15 VOLTS)

<TABLE cellSpacing=0 cellPadding=3 width="96%" border=1><TBODY><TR><TH>Test Step</TH><TH>Result / Action to Take</TH></TR><TR><TD>C1 CHECK FOR VOLTAGE DROP IN A CIRCUIT 35 (OG/LB)</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Disconnect: Generator C102a.
Measure the voltage drop between generator C102a pin A, circuit 35 (OG/LB), harness side and positive battery terminal.
http://www.gogodiesel.com/forum/filestorage/shopmanual/charging/A0043750.gif
Is the voltage drop less than 0.5 volt?
</TD><TD style="BORDER-TOP: medium none">Yes
GO to C2.

No
REPAIR the high resistance in A circuit 35 (OG/LB). TEST the system for normal operation.
</TD></TR><TR><TD>C2 CHECK GENERATOR AND BATTERY GROUND CONNECTIONS</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Key in OFF position.
Check the ground connections between the generator and the engine, and the battery and the engine.
Are all ground connections clean and tight?
</TD><TD style="BORDER-TOP: medium none">Yes
INSTALL a new generator. REFER to Section 414-02. TEST the system for normal operation.

No
REPAIR ground connections as necessary. TEST the system for normal operation.
</TD></TR></TBODY></TABLE>
PINPOINT TEST D: THE CHARGING SYSTEM WARNING INDICATOR IS ON WITH THE ENGINE RUNNING AND THE BATTERY INCREASES VOLTAGE

<TABLE cellSpacing=0 cellPadding=3 width="96%" border=1><TBODY><TR><TH>Test Step</TH><TH>Result / Action to Take</TH></TR><TR><TD>D1 CHECK I CIRCUIT 904 (LG/RD) FOR SHORT TO GROUND</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Disconnect: Generator C102a.
Key in ON position.
With the ignition switch in the ON position, check the charging system warning indicator.
Is the charging system warning indicator illuminated?
</TD><TD style="BORDER-TOP: medium none">Yes
REPAIR generator I circuit 904 (LG/RD). TEST the system for normal operation.

No
INSTALL a new generator. REFER to Section 414-02. TEST the system for normal operation.
</TD></TR></TBODY></TABLE>
PINPOINT TEST E: THE CHARGING SYSTEM WARNING INDICATOR IS OFF WITH THE IGNITION SWITCH IN THE RUN POSITION AND THE ENGINE OFF

<TABLE cellSpacing=0 cellPadding=3 width="96%" border=1><TBODY><TR><TH>Test Step</TH><TH>Result / Action to Take</TH></TR><TR><TD>E1 CHECK THE CHARGING SYSTEM WARNING INDICATOR</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Disconnect: Generator C102a.
With the engine off, connect a fused (15A) jumper wire between the generator C102a pin I, circuit 904 (LG/RD), harness side and ground.
http://www.gogodiesel.com/forum/filestorage/shopmanual/charging/A0041087.gif
Key in ON position.
Is the charging system warning indicator illuminated?
</TD><TD style="BORDER-TOP: medium none">Yes
INSTALL a new generator. REFER to Section 414-02. TEST the system for normal operation.

No
REFER to Section 413-01for diagnosis and testing of the instrument cluster.
</TD></TR></TBODY></TABLE>
PINPOINT TEST F: THE CHARGING SYSTEM WARNING INDICATOR LAMP FLICKERS OR IS INTERMITTENT

<TABLE cellSpacing=0 cellPadding=3 width="96%" border=1><TBODY><TR><TH>Test Step</TH><TH>Result / Action to Take</TH></TR><TR><TD>F1 CHECK FOR LOOSE CONNECTIONS</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Check all generator, battery, and power distribution connections for looseness, corrosion, loose or bent terminals, or loose eyelets.
Are all connections clean and tight?
</TD><TD style="BORDER-TOP: medium none">Yes
GO to F2.

No
REPAIR as necessary. TEST the system for normal operation.
</TD></TR><TR><TD>F2 CHECK FUSE CONNECTIONS</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Key in START position.
With the engine running, check the CJB fuse 45 (10A) in I circuit 904 (LG/RD) for looseness by wiggling the fuse and noting the charging system warning indicator operation.
Does the charging system warning indicator flicker?
</TD><TD style="BORDER-TOP: medium none">Yes
REPAIR loose fuse connection(s) as necessary. TEST the system for normal operation.

No
GO to F3.
</TD></TR><TR><TD>F3 CHECK A CIRCUIT 35 (OG/LB) CONNECTIONS</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Key in OFF position.
Connect a fused (15A) jumper wire between generator C102a, pin A, circuit 35 (OG/LB), harness side and the positive battery terminal.
http://www.gogodiesel.com/forum/filestorage/shopmanual/charging/A0067983.gif
Key in START position.
With the engine running, note the charging system warning indicator operation.
Does the charging system warning indicator flicker?
</TD><TD style="BORDER-TOP: medium none">Yes
INSTALL a new generator. REFER to Section 414-02. TEST the system for normal operation.

No
REPAIR loose connection(s) in circuits. TEST the system for normal operation.
</TD></TR></TBODY></TABLE>
PINPOINT TEST G: THE GENERATOR IS NOISY

<TABLE cellSpacing=0 cellPadding=3 width="96%" border=1><TBODY><TR><TH>Test Step</TH><TH>Result / Action to Take</TH></TR><TR><TD>G1 CHECK FOR ACCESSORY DRIVE NOISE</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Check the accessory drive belt for damage and correct installation. Check the accessory mounting brackets and generator pulley for looseness or misalignment.
Is the accessory drive OK?
</TD><TD style="BORDER-TOP: medium none">Yes
GO to G2.

No
REPAIR as necessary. REFER to Section 303-05 for diagnosis and testing of the accessory drive system. TEST the system for normal operation.
</TD></TR><TR><TD>G2 CHECK GENERATOR MOUNTING</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Check the generator mounting for loose bolts or misalignment.
Is the generator mounted correctly?
</TD><TD style="BORDER-TOP: medium none">Yes
GO to G3.

No
REPAIR as necessary. TEST the system for normal operation.
</TD></TR><TR><TD>G3 CHECK GENERATOR FOR ELECTRICAL NOISE</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

Disconnect: Generator C102a.
Key in START position.
With the engine running, use a stethoscope or equivalent listening device to probe the generator.
Is the noise still present?
</TD><TD style="BORDER-TOP: medium none">Yes
GO to G4.

No
INSTALL a new generator. REFER to Section 414-02. TEST the system for normal operation.
</TD></TR><TR><TD>G4 CHECK GENERATOR FOR MECHANICAL NOISE</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

With the engine running, use a stethoscope or equivalent listening device to probe the generator area for unusual mechanical noise.
Is the generator the noise source?
</TD><TD style="BORDER-TOP: medium none">Yes
INSTALL a new generator. REFER to Section 414-02. TEST the system for normal operation.

No
REFER to Section 303-00 to diagnose the source of the engine noise.
</TD></TR></TBODY></TABLE>
PINPOINT TEST H: RADIO INTERFERENCE

<TABLE cellSpacing=0 cellPadding=3 width="96%" border=1><TBODY><TR><TH>Test Step</TH><TH>Result / Action to Take</TH></TR><TR><TD>H1 VERIFY GENERATOR IS SOURCE OF RADIO INTERFERENCE</TD><TD style="BORDER-BOTTOM: medium none"></TD></TR><TR vAlign=top><TD>

NOTE: If the original equipment manufactured (OEM) radio unit has been replaced, the vehicle may not pass this test. Return the vehicle to OEM condition before following this pinpoint test.
Key in START position.
With the engine running, tune the radio to a station where the interference is present.
Key in OFF position.
Disconnect: Generator C102a.
Key in START position.
With the engine running, note any radio interference.
Is the interference present with the generator disconnected?
</TD><TD style="BORDER-TOP: medium none">Yes
REFER to Section 415-00 for diagnosis and testing of the in-vehicle entertainment system.

No
INSTALL a new generator. REFER to Section 414-02. TEST the system for normal operation.
</TD></TR></TBODY></TABLE>

PSDPlayer

07-27-2007, 12:42 PM

Component Tests

PSDPlayer

07-27-2007, 12:42 PM

Battery — Drain Tests
NOTE: A periodic pulsing of up to 80 mA (0.080 amp) is caused by the integrated control panel (ICP) and should be considered normal. However, no production vehicle should have more than a 50 mA (0.050 amp) continuous draw.
Check for current drains on the battery in excess of 50 milliamps (0.050 amp) with all the electrical accessories off and the vehicle at rest. Current drains can be tested with the following procedure:

WARNING: Do not attempt this test on a lead-acid battery that has recently been recharged. Explosive gases can cause personal injury.

CAUTION: To prevent damage to the meter, do not crank the engine or operate accessories that draw more than 10A.
NOTE: Many modules draw 10 mA (0.010 amp) or more continuously.
NOTE: Use an in-line ammeter between the battery positive or negative post and its respective cable.
NOTE: Typically, a drain of approximately one amp can be attributed to an engine compartment lamp, glove compartment lamp, or luggage compartment lamp staying on continually. Other component failures or wiring shorts may be located by selectively pulling fuses to pinpoint the location of the current drain. When the current drain is found, the meter reading will fall to an acceptable level. If the drain is still not located after checking all the fuses, it may be due to the generator.
NOTE: To accurately test the drain on a battery, an in-line digital ammeter must be used. Use of a test lamp or voltmeter is not an accurate method due to the number of electronic modules.

Make sure the junction box/fuse panels are accessible without turning on interior and underhood lights.
Drive the vehicle at least five minutes and over 48 km/h (30 mph) to turn on and exercise vehicle systems.
Allow the vehicle to sit with the key off for at least 40 minutes to allow modules to time out/power down.
Connect a fused jumper wire between the negative battery cable and the negative battery post to prevent modules from resetting and to catch capacitive drains.
Disconnect the negative battery cable from the post without breaking the connection of the jumper wire.
NOTE: It is very important that continuity is not broken between the battery and the negative battery cable when connecting the meter. If this happens, the entire procedure must be repeated.
Connect the tester between the negative battery cable and the post. The meter must be capable of reading milliamps and should have a 10 amp capability.
NOTE: If the meter settings need to be switched or the test leads need to be moved to another jack, the jumper wire must be reinstalled to avoid breaking continuity.
Remove the jumper wire.NOTE: Amperage draw will vary from vehicle to vehicle depending on the equipment package. Compare to a similar vehicle for reference.
NOTE: A periodic pulsing of up to 80 mA (0.080 amp) is caused by the integrated control panel (ICP) and should be considered normal. However, no production vehicle should have more than a 50 mA (0.050 amp) draw.

If the draw is found to be excessive, pull fuses from the battery/central junction box one at a time and note the current drop. Do not reinstall the fuses until you are finished testing.
Check the wiring schematic in the wiring diagram for any circuits that run from the battery without passing through the battery/central junction box. Disconnect these circuits if the draw is still excessive.

PSDPlayer

07-27-2007, 12:44 PM

Battery — Electronic Drains Which Shut Off When the Battery Cable is Disconnected

Repeat the steps of the battery drain testing.
Make sure all doors are closed and accessories are off. Without starting the engine, turn the ignition switch to ON for a moment and then OFF. Wait a few minutes for the illuminated entry lamps to turn off if equipped.
Connect the ammeter and read the amperage draw.The current reading (current drain) should be less than 50 mA (0.05 amp). If the current drain exceeds 50 mA (0.05 amp) after a few minutes, and if this drain did not show in previous tests, the drain is most likely caused by an inoperative electronic component. As in previous tests, remove the fuses from the battery/central junction box one at a time to locate the problem circuit.

PSDPlayer

07-27-2007, 12:45 PM

Generator On-Vehicle Tests

CAUTION: To prevent damage to the generator, do not make jumper wire connections except as directed.

CAUTION: Do not allow any metal object to come in contact with the housing and the internal diode cooling fins with key on or off. A short circuit will result and burn out the diodes.
NOTE: Battery posts and cable clamps must be clean and tight for accurate meter indications.
NOTE: Refer to the battery tester manual for complete directions for testing the charging system.

Turn off all lamps and electrical components.
Place the vehicle in transmission range NEUTRAL and apply the parking brake.
Carry out the Load Test and No-Load Test according to the following component tests:

PSDPlayer

07-27-2007, 12:46 PM

Generator On-Vehicle Tests — Load Test

Switch the tester to the ammeter function.
Connect the positive and negative leads of the tester to the corresponding battery terminals.
Connect the current probe to the generator B+ output terminal, circuit 36 (YE/WH).
With the engine running at 2,000 rpm, adjust the tester load bank to determine the output of the generator. Generator output should be at least 87 amps.http://www.gogodiesel.com/forum/filestorage/shopmanual/charging/A0006242.gif

With the engine running, turn the A/C on, the blower motor on high speed and the headlamps on high beam.
Increase the engine speed to approximately 2,000 rpm. The voltage should increase a minimum of 0.5 volt above the base voltage.
If the voltage does not increase as specified, carry out the Generator On-Vehicle Tests — No Load Test, in this section.
If the voltage increases as specified, the charging system is operating normally.

PSDPlayer

07-27-2007, 12:47 PM

Generator On-Vehicle Tests — No-Load Test

Switch the tester to the voltmeter function.
Connect the voltmeter positive lead to the generator B+ terminal and the negative lead to ground.
Turn all electrical accessories off.
With the engine running at 2,000 rpm, check the generator output voltage. The voltage should be between 13.0 and 15.0 volts. If not, refer to the Symptom Chart or back to the pinpoint test.