Horn System - Electrical Diagnostics: Other Jeep Commander I

Monitor Conditions

1. When Monitored: Continuously.

Set Conditions

1. Set Condition: If the Front Control Module (FCM) senses either excessively low or no voltage on the (X4) Horn Relay Control circuit.

Possible Causes

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

1. 1) TEST FOR INTERMITTENT CONDITION Turn the ignition on. With the scan tool, record and erase DTCs. Operate the Horn Switch several times. Cycle the ignition from on to off three times and leave on. With the scan tool, read DTCs. Does the scan tool display: B2336 HORN CONTROL CIRCUIT LOW? Yes Go to 2) . No The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
2. 2) CHECK THE HORN FUSE Turn the ignition off. Remove and inspect the Horn fuse. Is the Horn Fuse open? Yes Go to 3) . No Reinstall the Horn Fuse. Then, go to 7) .
3. 3) CHECK FOR A SHORTED HORN RELAY Install a known good relay in place of the Horn Relay. Replace the Horn fuse. Turn the ignition on. With the scan tool, record and erase DTCs. Operate the Horn Switch several times. Cycle the ignition from on to off three times and leave on. With the scan tool, read DTCs. Does the scan tool display: B2336 HORN CONTROL CIRCUIT LOW? Yes Go to 4) . No Replace the original Horn Relay. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
4. 4) CHECK THE (A43) FUSED B(+) CIRCUIT FOR A SHORT TO GROUND Turn the ignition off. Remove the Horn Relay. Remove the Horn Fuse. Measure the resistance of the (A43) Fused B(+) circuit between ground and Cavity 86 of the Horn Relay connector in the Integrated Power Module (IPM). Measure the resistance of the (A43) Fused B(+) circuit between ground and Cavity 30 of the Horn Relay connector in the Integrated Power Module (IPM). Is the resistance below 10k ohms? Yes Replace the Integrated Power Module (IPM) in accordance with the Service Information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Go to 5) .
5. 5) CHECK THE (X4) HORN RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND Remove the Front Control Module (FCM) in accordance with the Service Information. Measure the resistance of the (X4) Horn Relay Control circuit between ground and Cavity 85 of the Horn Relay connector in the Integrated Power Module (IPM). Is the resistance below 10k ohms? Yes Replace the Integrated Power Module (IPM) in accordance with the Service Information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Replace the Front Control Module (FCM) in accordance with the Service Information. Then, go to 6) .
6. 6) CHECK FOR A SHORTED INTEGRATED POWER MODULE (IPM) Install the original Horn Relay. Replace the Horn fuse. Turn the ignition on. With the scan tool, record and erase DTCs. Operate the Horn Switch several times. Cycle the ignition from on to off three times and leave on. With the scan tool, read DTCs. Does the scan tool display: B2336 HORN CONTROL CIRCUIT LOW? Yes Replace the Integrated Power Module (IPM) in accordance with the Service Information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
7. 7) CHECK FOR POWER TO THE HORN FUSE Turn the ignition on. Using a 12-volt test light connected to ground, check for power to the Horn Fuse. Does the test light illuminate brightly? Yes Go to 8) . No Repair the (A1) / (A913) circuit for an open. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
8. 8) CHECK FOR AN OPEN HORN RELAY Turn the ignition off. Install a known good relay in place of the Horn Relay. Turn the ignition on. With the scan tool, record and erase DTCs. Operate the Horn Switch several times. Cycle the ignition from on to off three times and leave on. With the scan tool, read DTCs. Does the scan tool display: B2336 HORN CONTROL CIRCUIT LOW? Yes Go to 9) . No Replace the original Horn Relay. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
9. 9) CHECK THE (A43) FUSED B(+) CIRCUIT FOR AN OPEN Turn the ignition off. Remove the Horn Relay. Remove the Horn Fuse. Measure the resistance of the (A43) Fused B(+) circuit between the Horn Fuse (output cavity) and Cavity 86 of the Horn Relay connector in the Integrated Power Module (IPM). Measure the resistance of the (A43) Fused B(+) circuit between the Horn Fuse (output cavity) and Cavity 30 of the Horn Relay connector in the Integrated Power Module (IPM). Is the resistance below 5.0 ohms? Yes Go to 10) . No Replace the Integrated Power Module (IPM) in accordance with the Service Information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
10. 10) CHECK THE (X4) HORN RELAY CONTROL CIRCUIT FOR AN OPEN Remove the Front Control Module (FCM) in accordance with the Service Information. Measure the resistance of the (X4) Horn Relay Control circuit between Cavity 85 of the Horn Relay connector in the Integrated Power Module (IPM) and Cavity 47 of the FCM 49-Way connector. Is the resistance below 5.0 ohms? Yes Replace the Front Control Module (FCM) in accordance with the Service Information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Replace the Integrated Power Module (IPM) in accordance with the Service Information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .

Scheme 10

1. When Monitored: Continuously.

1. Set Condition: If the Front Control Module (FCM) senses excessive voltage on the (X4) Horn Relay Control circuit.

Scheme 11

1. 1) TEST FOR INTERMITTENT CONDITION Turn the ignition on. With the scan tool, record and erase DTCs. Operate the Horn Switch several times. Cycle the ignition from on to off three times and leave on. With the scan tool, read DTCs. Does the scan tool display: B2337 HORN CONTROL CIRCUIT HIGH? Yes Go to 2) . No The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
2. 2) CHECK FOR A SHORTED HORN RELAY Turn the ignition off. Install a known good relay in place of the Horn Relay. Turn the ignition on. With the scan tool erase DTCs. Operate the Horn Switch several times. Cycle the ignition from on to off three times and leave on. With the scan tool, read DTCs. Does the scan tool display: B2337 HORN CONTROL CIRCUIT HIGH? Yes Go to 3) . No Replace the original Horn Relay. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
3. 3) CHECK THE (X4) HORN RELAY CONTROL CIRCUIT FOR A SHORT TO VOLTAGE Turn the ignition off. Remove the Horn Relay. Remove the Front Control Module (FCM) in accordance with the Service Information. Turn the ignition on. Measure the voltage of the (X4) Horn Relay Control circuit. Is the voltage above 0.2 volts? Yes Replace the Integrated Power Module (IPM) in accordance with the Service Information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Replace the Front Control Module (FCM) in accordance with the Service Information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .

Scheme 12

1. When Monitored: Continuously.

1. Set Condition: If the Steering Column Control Module (SCCM) senses that the Horn Switch is in the Set position for more than 50 seconds.

Scheme 13

Scheme 14

1. 1) TEST FOR INTERMITTENT CONDITION NOTE: If DTC P0562 BATTERY VOLTAGE LOW or DTC P0563 BATTERY VOLTAGE HIGH is active along with this DTC, diagnose and repair the battery voltage related DTC first. Refer to appropriate Engine ELECTRICAL DIAGNOSTICS article. Turn the ignition on. With the Scan Tool, select View DTCs in the Steering Column Control Module (SCCM). Does the scan tool display DTC B2339 HORN SWITCH STUCK active? Yes Go to 2) . No The conditions necessary to set this DTC are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. In addition, wiggle test the wiring and connectors while monitoring the scan tool data relative to this circuit. Look for the data to change or for the DTC to set as active during the wiggle test. Repair as necessary. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
2. 2) TEST THE HORN SWITCH Turn the ignition off. Remove the Driver Airbag in accordance with the Service information. Disconnect the Horn Switch connector. Measure the resistance between the (X3) Horn Switch Signal circuit and the (X903) Horn Switch Return circuit in the Horn Switch while pressing and releasing the switch several times. Does the ohmmeter reading indicate continuity when the switch is pressed and no continuity when the switch is released? Yes Go to 3) . No Replace the Horn Switch in accordance with the Service Information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .
3. 3) CHECK THE (X3) HORN SWITCH SIGNAL CIRCUIT FOR A SHORT TO THE (X903) HORN SWITCH RETURN CIRCUIT Disconnect the Steering Control Module C3 connector. Measure the resistance between the (X3) Horn Switch Signal circuit and the (X903) Horn Switch Return circuit in the Horn Switch Connector. Is the resistance below 10k ohms? Yes Repair the (X3) Horn Switch Signal circuit for a short to the (X903) Horn Switch Return circuit. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Go to 4) .
4. 4) CHECK THE (X3) HORN SWITCH SIGNAL CIRCUIT FOR A SHORT TO GROUND Measure the resistance between ground and the (X3) Horn Switch Signal circuit in the Horn Switch Connector. Is the resistance below 10k ohms? Yes Repair the (X3) Horn Switch Signal circuit for a short to ground. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) . No Replace the Steering Column Control Module (SCCM) in accordance with the Service Information. Perform «BODY VERIFICATION TEST»(ref-288232-S30638820392008062000000) .