Anti-Theft System Test 4A - Repairing Anti-Theft System Horn Circuit
NOTE:
Perform ANTI-THEFT SYSTEM TEST 1A
before proceeding. For connector terminal ID, see CONNECTOR IDENTIFICATION
and WIRING DIAGRAM. See ANTI-THEFT SYSTEM article. Perform TEST VER-2A
after each repair.
CAUTION:
Always turn ignition switch to OFF position prior to disconnecting any module connector. Ensure all connectors are clean and tight.
- Turn ignition switch to on position. Press horn button. If horn does not sound, go to step 3). If horn sounds, turn ignition off. Disconnect Body Control Module (BCM) White 24-pin connector. BCM is located under left side of dash.
- Momentarily connect a jumper wire between BCM White 24-pin connector terminal No. 13 (Gray/Orange wire) and chassis ground. If horn does not sound, repair open in Gray/Orange wire. If horn sounds, replace BCM.
- Remove horn relay. Horn relay is located in power distribution center. Power distribution center is located in engine compartment. Using an ohmmeter, check resistance between horn relay terminals No. 85 and 86. See Fig 1 . If resistance is less than 65 ohms or more than 90 ohms, replace relay. If resistance is more than 65 ohms or less than 90 ohms, go to next step.
- Using scan tool in voltmeter mode, probe horn relay connector terminal No. 86. If voltage is less than 10 volts, replace power distribution center. If voltage is 10 volts or more, go to next step.
- Connect a test light between horn relay connector terminals No. 85 (Gray/Orange wire) and No. 86 (Violet wire). Press horn button while observing test light. If test light does not flash when horn button is pressed, repair open in Gray/Orange wire. If test light flashes when horn button is pressed, go to next step.
- Connect a jumper wire between horn relay connector terminals No. 30 (Violet wire) and No. 87 (Dark Green/Yellow wire). If horn sounds, replace horn relay. If horn does not sound, go to next step.
- Disconnect connector from on both horns. Connect one horn connector with a jumper wire to chassis ground. With scan tool in ohmmeter mode, probe horn relay connector terminal No. 87 (Dark Green/Yellow wire). If resistance is more than 5 ohms, repair open in Dark Green/Yellow wire. If resistance is 5 ohms or less, go to next step.
- Disconnect jumper wire. Using scan tool in ohmmeter mode, probe horn relay connector terminal No. 87 (Dark Green/Yellow wire). If resistance is less than 100 ohms, repair short in Dark Green/Yellow wire. If resistance is 100 ohms or more, replace horns.