Possible Causes
WARNING: This page is about a different car, the 2004 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.
An AIR BAG warning light that is continuously illuminated may be caused by disconnected RCM, damaged battery or ignition circuit, loss of ground circuit to RCM, inoperative RCM or faulty shorting bar or camming beam in connector.
- Check for hard or intermittent DTC
Turn ignition switch to OFF position. Connect scan tool to DLC. Turn ignition switch to ON position. Retrieve and record any continuous DTCs. See RETRIEVING FAULT CODES under DIAGNOSTICS. Perform on-demand self-test. See ON-DEMAND SELF-TEST . If continuous DTCs were retrieved, go to next step. If on-demand DTCs were retrieved, go to diagnostic trouble code identification table for direction to appropriate test. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION table. If no DTCs were retrieved, go to next step. - Check RCM connection
Turn ignition switch to OFF position. Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM . Access Restraints Control Module (RCM). See RESTRAINTS CONTROL MODULE (RCM) under REMOVAL & INSTALLATION. Ensure RCM harness connector is fully connected and Red locking tab is engaged. If RCM harness connector is fully connected and Red locking tab is engaged, go to next step. If RCM harness connector is not fully connected and/or Red locking tab is not engaged, reconnect connector and engage locking tab. Go to step 7 . - Check Orange/Yellow wire for open
Turn ignition switch to ON position. Disconnect RCM harness connector. Measure voltage between ground and RCM harness connector C2041, terminal No. 2 (Orange/Yellow wire, circuit No. 1654). See Fig 1 . Measure voltage between ground and RCM harness connector C2041, terminal No. 13 (Orange/Yellow wire.). If voltage is 9-16 volts in both circuits, go to next step. If voltage is not 9-16 volts in either circuit, repair open in appropriate wire. See WIRING DIAGRAMS . Go to step 7 . - Check Black/White wire for open
Turn ignition switch to OFF position. Measure resistance between ground and RCM harness connector C2041, terminal No. 21 (Black/White wire, circuit No. 570). If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open in Black/White wire. Go to step 7 . - Check Black/Yellow wire for short to ground
Access instrument cluster and disconnect harness connector C220B. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Measure resistance between ground and instrument cluster harness connector C220B, terminal No. 13 (Black/Yellow wire, circuit No. 608). See Figure . If resistance is more than 10 k/ohms, replace RCM. Go to step 7 . If resistance is less than 10 k/ohms, go to next step. - Check RCM
Measure resistance between ground and component side of RCM connector, terminal No. 20. See Fig 2 . If resistance is more than 10 k/ohms, repair Black/Yellow wire as necessary. Go to step 7 . If resistance is less than 10 k/ohms, replace RCM. Go to step 7 . - Check for additional DTCs
Refer to continuous DTCs recorded in step 1 . If any continuous DTCs were retrieved, go to diagnostic trouble code identification table for direction to appropriate test. DO NOT clear any DTCs until all DTCs have been resolved. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION table. If no DTCs were retrieved, reconnect air bag system. Activate air bag system. See ACTIVATING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Perform system operation check. See SYSTEM OPERATION CHECK . Clear all DTCs. See CLEARING FAULT CODES under DIAGNOSTICS.