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Home >> Ford >> 2000 >> Excursion 7.3 F, 4WD >> Repair and Diagnosis (Single Page) >> Restraints >> Air Bag, SRS >> Supplemental Inflatable Restraint System - Excursion & Super Duty >> Diagnostic Tests >> Test Q: Passenger Air Bag Deactivation (Pad) Switch Warning Light Short To Battery (DTC B1890) >> Possible Causes

Possible Causes

A short to battery on PAD switch warning light circuit could be caused by an short to battery on circuit 1113 (Yellow/Light Green wire), damaged or inoperative PAD switch or damaged or inoperative ECS.

  1. Check for hard or intermittent DTC

    Ensure ignition is off. Connect scan tool to DLC. See USING SCAN TOOL  under DIAGNOSTICS. Turn ignition switch to RUN position. Retrieve and record any continuous DTCs. See RETRIEVING FAULT CODES  under DIAGNOSTICS. Perform on-demand self-test. See ON-DEMAND SELF-TEST  under DIAGNOSTICS. If DTC B1890 was retrieved during on-demand self-test, fault is hard. Go to next step. If DTC B1890 was not retrieved, fault is intermittent. Go to step  4.

  2. Check PAD switch warning light

    Place PAD switch in OFF position. If PAD warning light illuminates properly, replace ECS. Go to step  5. If PAD warning light does not illuminate properly, go to next step.

  3. Check circuit for short to battery

    Turn ignition off. Disable air bag system. See DISABLING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Leave negative battery cable disconnected. Access ECS and disconnect harness connector. See ELECTRONIC CRASH SENSOR  under REMOVAL & INSTALLATION. Access PAD switch and disconnect connector. See PASSENGER-SIDE AIR BAG DEACTIVATE (PAD) SWITCH  under REMOVAL & INSTALLATION. Turn ignition switch to RUN position. Measure resistance between ECS connector terminals No. 8 (Yellow/Light Green wire) and No. 17 (Red/White wire). See Figure. If resistance is less than 100 ohms, repair short to battery in Yellow/Light Green wire. Go to step  5. If resistance is more than 100 ohms, replace PAD switch. Go to step  5.

  4. Check for intermittent fault

    Refer to continuous DTCs recorded in step  1. If DTC retrieved in step  1 was an intermittent fault, check for cause of intermittent short to battery on circuit 1113 (Yellow/Light Green wire). Attempt to recreate fault by flexing wire harness and cycling ignition switch frequently. Repair any intermittent problems found. go to next step. If DTC retrieved in step  1 was not an intermittent fault, go to next step.

  5. 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. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION  table. If no continuous DTCs were retrieved, reconnect air bag system. Activate air bag system. See ACTIVATING SYSTEM  under DISABLING & ACTIVATING AIR BAG SYSTEM. Prove out system. Clear all DTCs. See CLEARING FAULT CODES  under DIAGNOSTICS.
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