Test F: Ignition Switch Inoperative
WARNING: This page is about a different car, the 2002 Mercury Sable, 2002 Ford Taurus, 2001 Mercury Sable, and 2001 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Perform all voltage and resistance tests using a Digital Volt-Ohm Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.
- Turn ignition switch to LOCK position. Remove and inspect fuse No. 7 (40-amp) from Battery Junction Box (BJB). See Figure. If fuse is blown, replace fuse. If fuse blows again, go to next step. If fuse does not blow again, go to step 4.
- Disconnect negative and positive battery cables. Measure negative and positive battery cable resistance. If resistances are less than 5 ohms, go to next step. If any resistance is 5 ohms or greater, repair or replace appropriate faulty battery cable. After repair, test system for normal operation.
- Connect negative and positive battery cables. Ensure ignition switch is in LOCK position. Disconnect ignition switch 15-pin harness connector C250, located on steering column. See Figure. Measure voltage between ground and ignition switch harness connector C250 terminals B1, B3, B4 and B5 (Light Green/Violet wires). See Fig 1. See WIRING DIAGRAMS . If voltages are greater than 10 volts at all terminals, go to next step. If any voltage is 10 volts or less, repair open circuit in appropriate Light Green/Violet wire(s) between ignition switch and BJB. After repair, test system for normal operation.
- Perform ignition switch component test. See IGNITION SWITCH under COMPONENT TESTS. If ignition switch is okay, replace BJB. If ignition switch is faulty, replace ignition switch. See IGNITION SWITCH under REMOVAL & INSTALLATION. After repair, test system for normal operation.