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Generators & Regulators: Diagnosis Ford Thunderbird XI

Charging System 2 illustrations ~2171 words

TROUBLE SHOOTING

Note. For trouble shooting charging system, see BASIC TROUBLE SHOOTING article in GENERAL INFORMATION.

Verify customer's concern. Verify battery condition. Inspect accessory drive belt and tensioner. Inspect battery junction box fuse No. 20 (5-amp). Inspect central junction box fuse No. 17 (5-amp). Check all connections for looseness or corrosion. If problem is found, repair as necessary. If problem is not found, perform self-diagnostics. See SELF-DIAGNOSTIC SYSTEM .

BATTERY DRAIN TEST

  1. Ensure junction box/fuse panels are accessible without turning on interior and hood lights. Drive vehicle over 30 MPH for at least 5 minutes. Park vehicle and allow to sit with ignition off for at least 40 minutes to allow electronic modules to power down. Go to next step.
  2. Connect a fused jumper wire between negative battery cable and negative battery post. Disconnect negative battery cable from negative battery post, without breaking the jumper wire connection to prevent modules from resetting. Go to next step. NOTE: It is very important that continuity is not broken between negative battery post and negative battery cable when disconnecting battery cable or connecting ammeter. If continuity is broken, go to step 1 .
  3. Ensure ammeter is set to read milliamps with at least a 10 amp capability. Connect ammeter between negative battery cable and negative battery post. Remove fused jumper wire. Go to next step.
  4. If excessive current draw is present, pull fuses from battery/central junction box one at a time and note any current drop when each fuse is removed. DO NOT reinstall fuses until test is complete. Go to next step.
  5. Check wiring diagrams for any circuits that run from battery without passing through battery/central junction box. Disconnect these circuits if current draw still exists.

BATTERY DRAINS THAT SHUT OFF WHEN BATTERY CABLE IS DISCONNECTED TEST

  1. Perform battery drain test. See «BATTERY DRAIN TEST»(ref-163638-S39524838462004070800000) . Ensure all doors are closed and accessories are off. Without starting engine, turn ignition switch to RUN position for a moment, and then turn ignition OFF. Wait a few minutes for illuminated entry lamps to turn off (if equipped).
  2. Connect ammeter between negative battery cable and negative battery post. Disconnect negative battery cable from negative battery post, without breaking the ammeter connection to prevent modules from resetting. Read amperage draw.
  3. Amperage draw should be less than 50 milliamps. If current draw exceeds 50 milliamps, remove fuses from battery/central junction box one at a time to locate problem circuit.

GENERATOR LOAD TEST

  1. Ensure drive belt is in good condition. Replace belt as necessary. If belt is okay, connect charging system load tester in accordance with manufacturer's instructions. Start and run engine at 2000 RPM, and apply load until generator output levels off. Generator amperage should be at least 58 amps with engine at 2000 RPM. Go to next step.
  2. Turn A/C system on. Turn blower speed to high. Turn headlights on to high beams. Voltage should increase a minimum of .5 volts. If voltage is as specified, system is operating properly at this time. If voltage is not as specified, perform «GENERATOR NO-LOAD TEST»(ref-163638-S25821007882004070800000) .

GENERATOR NO-LOAD TEST

Switch tester to voltmeter function. Connect voltmeter positive lead to B+ terminal on generator and negative lead to ground. Turn all electrical accessories off. Start and run engine up to 2000 RPM. Read voltmeter when voltage stabilizes. Voltage should be 13-15 volts. If voltage is not as specified, repair by symptom. See SYMPTOM INDEX table under SYSTEM TESTS.

SELF-DIAGNOSTIC SYSTEM

Connect New Generation Star (NGS) tester to Data Link Connector (DLC). Using NGS tester, perform Powertrain Control Module (PCM) self-test. If any DTCs exist, perform appropriate test in accordance with DTC retrieved. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. If no DTCs are present, repair by symptom. See SYMPTOM INDEX table under SYSTEM TESTS.

TEST A: BATTERY IS DISCHARGED OR VOLTAGE IS LOW

  1. Perform generator load and no-load tests. See «GENERATOR LOAD TEST»(ref-163638-S04182786062004070800000) and «GENERATOR NO-LOAD TEST»(ref-163638-S25821007882004070800000) under ON-VEHICLE TESTING. If generator is okay, go to next step. If generator is not okay, perform «TEST B: WARNING INDICATOR ON WITH ENGINE RUNNING, SYSTEM NOT CHARGING»(ref-163638-S42757760562004070800000) .
  2. Perform «BATTERY DRAIN TEST»(ref-163638-S39524838462004070800000) under ON-VEHICLE TESTING. If no excessive current draw was not found, go to next step. If any excessive current draw was found, repair as necessary.
  3. Perform «BATTERY DRAINS THAT SHUT OFF WHEN BATTERY CABLE IS DISCONNECTED TEST»(ref-163638-S16772099132004070800000) under ON-VEHICLE TESTING. If there are any current drains that shut off when the battery is disconnected, repair as necessary. If no drains were found, perform «TEST B: WARNING INDICATOR ON WITH ENGINE RUNNING, SYSTEM NOT CHARGING»(ref-163638-S42757760562004070800000) .

Scheme 1

Scheme 1: TEST B: WARNING INDICATOR ON WITH ENGINE RUNNING, SYSTEM NOT CHARGING
Scheme 1: TEST B: WARNING INDICATOR ON WITH ENGINE RUNNING, SYSTEM NOT CHARGING

Scheme 2

Scheme 2
Scheme 2
  1. Connect New Generation Star (NGS) tester to Data Link Connector (DLC). Turn ignition on. Using NGS tester, perform Powertrain Control Module (PCM) self-test. If no DTCs are retrieved, go to next step. If any Diagnostic Trouble Codes (DTC) are retrieved, perform appropriate test in accordance with DTC retrieved. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-132995-S13925953232002020800000) in SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
  2. Turn ignition off. Disconnect NGS tester. Disconnect generator 3-pin harness connector. Turn ignition on. Measure voltage between ground and generator harness connector terminal No. 2 (Gray/Red wire). (Scheme 1) If voltage is not present, go to next step. If voltage is present, go to step 4.
  3. Turn ignition off. Disconnect PCM harness connector C175c. Measure resistance of Gray/Red wire between generator harness connector terminal No. 2 and PCM harness connector C175c terminal No. 28. (Scheme 2) If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open in Gray/Red wire between generator and PCM.
  4. Connect PCM harness connector C175c. Connect generator 3-pin harness connector. Check generator output. Perform «GENERATOR LOAD TEST»(ref-163638-S04182786062004070800000) and «GENERATOR NO-LOAD TEST»(ref-163638-S25821007882004070800000) under ON-VEHICLE TESTING. If generator is okay, go to next step. If generator is not okay, replace generator. See «GENERATOR»(ref-163638-S28188765712004070800000) under REMOVAL & INSTALLATION.
  5. Disconnect PCM harness connector C175c. Inspect harness connector for pushed out pins, corrosion or bent terminals. Repair as necessary. If harness connector is okay, reconnect and retest system operation. If fault is still present, replace PCM. Clear DTCs and repeat PCM self-test. If fault is still not present, system is operating correctly at this time.

TEST C: SYSTEM OVERCHARGES

  1. Connect New Generation Star (NGS) tester to Data Link Connector (DLC). Turn ignition on. Using NGS tester, perform Powertrain Control Module (PCM) self-test. If no DTCs are retrieved, go to next step. If any Diagnostic Trouble Codes (DTC) are retrieved, perform appropriate test in accordance with DTC retrieved. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-132995-S13925953232002020800000) in SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
  2. Turn ignition off. Reconnect generator 3-pin harness connector. Start engine. Check generator output. See «GENERATOR LOAD TEST»(ref-163638-S04182786062004070800000) under ON-VEHICLE TESTING. If generator tests okay, go to next step. If generator does not test okay, replace generator. See «GENERATOR»(ref-163638-S28188765712004070800000) under REMOVAL & INSTALLATION.
  3. Turn ignition off. Disconnect generator 3-pin harness connector. Turn ignition on. Measure voltage between ground and generator harness connector terminal No. 3 (Red wire). (Scheme 1) If voltage is less than.5 volt from battery voltage, replace generator. See «GENERATOR»(ref-163638-S28188765712004070800000) under REMOVAL & INSTALLATION. If voltage is greater than.5 volt from battery voltage, repair high resistance in Red wire. See «WIRING DIAGRAMS»(ref-163638-S06360798042004070800000).

TEST D: WARNING INDICATOR ON WITH ENGINE RUNNING, SYSTEM IS CHARGING

  1. Connect New Generation Star (NGS) tester to Data Link Connector (DLC). Turn ignition on. Using NGS tester, perform Powertrain Control Module (PCM) self-test. If no DTCs are retrieved, go to next step. If any Diagnostic Trouble Codes (DTC) are retrieved, perform appropriate test in accordance with DTC retrieved. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-132995-S13925953232002020800000) in SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
  2. Turn ignition off. Disconnect NGS tester. Start engine. With engine running and all accessories turned off, measure voltage between battery terminals while varying engine speed. If voltage is less than 15 volts, go to next step. If voltage is greater than 15 volts, perform «TEST C: SYSTEM OVERCHARGES»(ref-163638-S13590840132004070800000).
  3. Turn ignition off. Disconnect generator 3-pin harness connector. Turn ignition on. Measure voltage between ground and generator harness connector terminal No. 3 (Red wire). (Scheme 1) If battery voltage is present, go to next step. If battery voltage is not present, repair open or short in Red wire. See «WIRING DIAGRAMS»(ref-163638-S06360798042004070800000).
  4. Turn ignition off. Disconnect PCM harness connector C175c. Turn ignition on and observe warning indicator. If warning indicator is not illuminated, go to next step. If warning indicator is illuminated, repair short to ground in Gray/Red wire between generator and PCM. See «WIRING DIAGRAMS»(ref-163638-S06360798042004070800000).
  5. Turn ignition off. Reconnect PCM harness connector C175c. Reconnect generator 3-pin harness connector. Check generator output. See «GENERATOR LOAD TEST»(ref-163638-S04182786062004070800000) under ON-VEHICLE TESTING. If generator tests okay, go to next step. If generator does not test okay, replace generator. See «GENERATOR»(ref-163638-S28188765712004070800000) under REMOVAL & INSTALLATION.
  6. Disconnect PCM harness connector C175c. Inspect harness connector for pushed out pins, corrosion or bent terminals. Repair as necessary. If harness connector is okay, reconnect and retest system operation. If fault is still present, replace PCM. Clear DTCs and repeat PCM self-test. If fault is still not present, system is operating correctly at this time.

TEST E: WARNING INDICATOR OFF WITH IGNITION ON

  1. Connect New Generation Star (NGS) tester to Data Link Connector (DLC). Turn ignition on. Using NGS tester, perform Powertrain Control Module (PCM) self-test. If no DTCs are retrieved, go to next step. If any Diagnostic Trouble Codes (DTC) are retrieved, perform appropriate test in accordance with DTC retrieved. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-132995-S13925953232002020800000) in SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
  2. Turn ignition off. Disconnect NGS tester and generator 3-pin harness connector. Turn ignition on. Connect a fused (15-amp) jumper wire between generator harness connector terminal No. 2 (Gray/Red wire) and ground. (Scheme 1) If warning indicator does not illuminate, go to next step. If warning indicator illuminates, replace generator. See «GENERATOR»(ref-163638-S28188765712004070800000) under REMOVAL & INSTALLATION.
  3. Disconnect PCM harness connector C175c. Inspect harness connector for pushed out pins, corrosion or bent terminals. Repair as necessary. If harness connector is okay, reconnect and retest system operation. If fault is still present, replace PCM. Clear DTCs and repeat PCM self-test. If fault is still not present, system is operating correctly at this time.

TEST F: WARNING INDICATOR FLICKERS, OR IS INTERMITTENT

  1. Connect New Generation Star (NGS) tester to Data Link Connector (DLC). Turn ignition on. Using NGS tester, perform Powertrain Control Module (PCM) self-test. If no DTCs are retrieved, go to next step. If any Diagnostic Trouble Codes (DTC) are retrieved, perform appropriate test in accordance with DTC retrieved. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-132995-S13925953232002020800000) in SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
  2. Disconnect generator 3-pin harness connector. Inspect generator, battery and battery junction box for looseness, corrosion or bent terminals. Clean and tighten any loose connection. If connections are okay, reconnect generator harness connector and go to next step.
  3. Start engine. With engine running, inspect battery junction box fuse No. 20 (5-amp), by wiggling fuse and observing warning indicator. If warning indicator flickers, repair loose fuse connection. Retest system operation. If warning indicator does not flicker, go to next step.
  4. With engine running and all accessories turned off, measure voltage between battery terminals. If battery voltage is less than 15 volts, go to next step. If battery voltage is greater than 15 volts, perform «TEST C: SYSTEM OVERCHARGES»(ref-163638-S13590840132004070800000).
  5. Turn ignition off. Disconnect generator 3-pin harness connector. Connect a fused (15-amp) jumper wire between generator harness connector terminal No. 2 (Gray/Red wire) and ground. (Scheme 1) Turn ignition on and observe warning indicator. If warning indicator illuminates, install a new generator. See «GENERATOR»(ref-163638-S28188765712004070800000) under REMOVAL & INSTALLATION. If warning indicator does not illuminate, inspect Gray/Red wire for open or ground between PCM connector and generator connector. If Gray/Red wire is okay, go to next step.
  6. Disconnect PCM harness connector C175c. Inspect harness connector for pushed out pins, corrosion or bent terminals. Repair as necessary. If harness connector is okay, reconnect and retest system operation. If fault is still present, replace PCM. Clear DTCs and repeat PCM self-test. If fault is still not present, system is operating correctly at this time.

TEST G: GENERATOR NOISY

  1. Turn ignition off. Check accessory drive belt for damage and correct installation. Check mounting brackets and pulleys for looseness and damage. If problem does not exist, go to next step. If problem exists, repair as necessary.
  2. Disconnect generator 3-pin harness connector. Start engine and let idle. Turn headlights on. Turn rear defogger on. Turn blower motor to high speed. If noise still exists, go to next step. If noise does not still exist, replace generator.
  3. Turn ignition off. Connect generator harness connector. Start engine and let idle. Turn all accessories off. Using a stethoscope, check generator for unusual mechanical noise. If generator is source of noise, replace generator. If generator is not source of noise, isolate noise and repair as necessary.

TEST H: RADIO INTERFERENCE

Start engine and let idle. Tune radio to station where interference is present. Turn ignition off. Disconnect generator 3-pin harness connector. Start engine and let idle. If interference is still present, repair radio concern. If interference is not still present, replace generator.

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