Starting System: Diagnosis Ford Taurus IV

TROUBLE SHOOTING

Check battery for state of charge. Check cable connections at battery and starter motor. Ensure transmission is fully engaged in Park or Neutral. Ensure Mega-fuse FB (175-amp) in Battery Junction Box (BJB) is okay. Check fuse F107 (40-amp) in BJB. Check fuse F237 (15-amp) in Central Junction Box (CJB). On models equipped with anti-theft system, ensure anti-theft system is operating properly (horn honks, lights flash, etc.) See PASSIVE ANTI-THEFT SYSTEMS - SABLE & TAURUS article in ACCESSORIES & EQUIPMENT for additional information. If problem is found, repair as necessary. If problem is not found, repair by symptom. See SYMPTOM INDEX table under SYSTEM TESTS.

ON-VEHICLE TESTING

VOLTAGE DROP TEST

Note. Make all voltmeter connections at component terminal rather than at cable or wire end.

Scheme 2

1. Verify battery condition. Battery voltage should be 12 volts or more. Load test battery at approximately one-half cold cranking amperage rating. See load tester manufacturer's instructions. If battery voltage is less than 12 volts or loaded battery voltage is less than 9.6 volts, service battery or charging system as necessary.
2. Disconnect inertia fuel shut off switch. Connect remote starter switch between starter solenoid terminal "S" and positive battery post. (Scheme 2)
3. Connect positive voltmeter lead to positive battery post, and negative lead to solenoid terminal "M". (Scheme 2)
4. Engage remote starter switch. Voltmeter should indicate.5 volt or less. If voltmeter indicates more than.5 volt, go to next step. If voltmeter indicates.5 volt or less, go to «STARTER GROUND CIRCUIT TEST»(ref-37885-S26640938092001011000000).
5. Move negative voltmeter lead to solenoid terminal "B". Engage remote starter switch. (Scheme 2) If voltmeter still indicates more than.5 volt at terminal "B", go to next step. If voltmeter indicates less than.5 volt, solenoid connections or contacts are bad. Clean solenoid terminals "B", "S" and "M". Repeat steps 2 - 5. If voltmeter still indicates more than.5 volt at terminal "M" and less than.5 volt at terminal "B", solenoid contacts are bad. Replace solenoid or entire starter assembly. See «STARTER MOTOR»(ref-37885-S03487608032001011000000) under REMOVAL & INSTALLATION.
6. Clean cables and connections at solenoid and battery. If voltmeter still indicates more than.5 volt at terminal "B", replace battery cable. NOTE: To locate excessive voltage drop, move voltmeter negative lead toward battery, and check each connection point. When high voltmeter reading disappears, problem is between last connection point and previous connection point.

STARTER GROUND CIRCUIT TEST

Note. Make all voltmeter connections at component terminal rather than at cable or wire end.

1. Disconnect inertia fuel shut off switch. Connect remote starter switch between starter solenoid terminal "S" and positive battery post.
2. Connect positive voltmeter lead to starter housing, and negative lead to negative battery post. Engage remote starter switch while observing voltmeter. Voltmeter should indicate .3 volt or less. If voltmeter indicates more than .3 volt, clean negative cable connections at battery and engine.
3. If voltage drop is still excessive, repair or replace negative battery cable and/or engine ground cable as necessary. Repeat starter circuit test after repair to ensure problem has been corrected. If battery and cables test okay and starter motor still cranks slowly, replace starter.

STARTER CIRCUIT CURRENT DRAW TEST

Ensure battery is fully charged. Ensure battery connections are clean and tight. Disconnect inertia fuel shut off switch. Connect Starter, Alternator, Battery, Regulator Electrical Tester (Rotunda 010-00730). Follow tool manufacturer's instructions. If tester is not available, use conventional ammeter. Clamp inductive ammeter lead around all positive (or negative) battery cables. (Scheme 3) Crank engine for about 5 seconds and check amperage reading while cranking. Normal amperage draw is 140-220 amps. If amperage draw exceeds specification, replace starter.

Scheme 3

TEST B: UNUSUAL STARTER NOISE

1. Ensure starter bolts and brackets are secure. Connect a remote starter switch between starter solenoid "B" (battery cable) and "S" (White/Pink wire) terminals. Activate remote starter switch to determine if unusual noise is due to starter operation. If noise is due to starter operation, go to next step. If noise is not due to starter operation, diagnose engine mechanical problem. See appropriate article in ENGINES.
2. Remove starter motor. See «STARTER MOTOR»(ref-37885-S03487608032001011000000) under REMOVAL & INSTALLATION. Inspect flywheel ring gear for wear or damage. If wear or damage is found, repair or replace as necessary. If flywheel ring gear is okay, replace starter motor.

STARTER NO-LOAD TEST

Remove starter from vehicle. See STARTER MOTOR under REMOVAL & INSTALLATION. Using heavy gauge jumper wires, connect battery positive to starter terminal "B", and negative battery terminal to starter frame. (Scheme 3) Connect voltmeter, ammeter, and remote starter switch to starter. Engage remote starter switch. Starter should turn smoothly. Ammeter should indicate 60-80 amps. If current is higher than specification, replace or overhaul starter.