Dodge Ram Truck 1500-2500-3500. Manual — part 348

*HORNS INOPERATIVE (CONTINUED)

9.

HORN GROUND CIRCUIT OPEN

Turn the ignition off.

Disconnect the Horn connector.

Using a 12-volt test light connected to 12-volts, check the Ground cir-
cuit in the horn connector.

Does the test light illuminate brightly?

Yes

>> Replace the Horns.

Perform BODY VERIFICATION TEST - VER 1. (Refer to 8
-

ELECTRICAL/ELECTRONIC

CONTROL

MODULES/

FRONT CONTROL MODULE - DIAGNOSIS AND TEST-
ING)

No

>> Repair the Ground circuit for an open.

Perform BODY VERIFICATION TEST - VER 1.

10.

HORN RELAY OUTPUT CIRCUIT OPEN

Gain access to the IPM C1 connector.

Using a 12-volt test light connected to ground, back probe the Horn
Relay Output circuit in the IPM C1 connector.

Turn the ignition on.

With the DRBIII

T

, the actuate the horn relay.

Does the test light illuminate brightly?

Yes

>> Repair the Horn Relay Output circuit for an open.

Perform BODY VERIFICATION TEST - VER 1. (Refer to 8
-

ELECTRICAL/ELECTRONIC

CONTROL

MODULES/

FRONT CONTROL MODULE - DIAGNOSIS AND TEST-
ING)

No

>> Go To 11

8H - 16

HORN SYSTEM - ELECRICAL DIAGNOSTICS

DR/DH

*HORNS INOPERATIVE (CONTINUED)

11.

INTEGRATED POWER MODULE

Turn the ignition off.

Remove the Front Control Module from the Integrated Power Module.

NOTE: Check connectors - Clean/repair as necessary.

NOTE: The test light is still connected to the C1 connector.
Momentarily jumper the Horn Relay Control circuit to ground at the
FCM connector.

Does the test light illuminate brightly?

Yes

>> Replace the Front Control Module in accordance with the

Service Information.

Perform BODY VERIFICATION TEST - VER 1. (Refer to 8
-

ELECTRICAL/ELECTRONIC

CONTROL

MODULES/

FRONT CONTROL MODULE - DIAGNOSIS AND TEST-
ING)

No

>> Replace the Integrated Power Module in accordance with the Service Information.

Perform BODY VERIFICATION TEST - VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING)

DR/DH

HORN SYSTEM - ELECRICAL DIAGNOSTICS

8H - 17

SCHEMATICS AND DIAGRAMS

HORN

SYSTEM

8H - 18

HORN SYSTEM - ELECRICAL DIAGNOSTICS

DR/DH

HORN SYSTEM - SERVICE INFORMATION

TABLE OF CONTENTS

page

page

HORN SYSTEM - SERVICE INFORMATION

DESCRIPTION

. . . . . . . . . . . . . . . . . . . . . . . . . 19

OPERATION

. . . . . . . . . . . . . . . . . . . . . . . . . . . 19

DIAGNOSIS AND TESTING

HORN SYSTEM

. . . . . . . . . . . . . . . . . . . . . . . 19

HORN

DIAGNOSIS AND TESTING

HORN

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

REMOVAL

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

INSTALLATION

. . . . . . . . . . . . . . . . . . . . . . . . . 20

SWITCH-HORN

DESCRIPTION

. . . . . . . . . . . . . . . . . . . . . . . . . 21

DIAGNOSIS AND TESTING

HORN SWITCH

. . . . . . . . . . . . . . . . . . . . . . . 21

HORN SYSTEM - SERVICE INFORMATION

DESCRIPTION

The dual-note horn system features two electromagnetic horn units. The horn system includes the following major
components:

•

Horn - The two horns are located on the left side of the engine compartment below the Integrated Power
Module (IPM).

•

Horn Switch - The horn switch is molded into the driver airbag trim cover.

OPERATION

The horn system operates on battery current received through a fuse in the Integrated Power Module (IPM). The
horn system circuit is designed so that the system will remain operational, regardless of the ignition switch position.

DIAGNOSIS AND TESTING

HORN SYSTEM

The most reliable, efficient, and accurate means to diagnose the horn system requires the use of a scan
tool and the proper Diagnostic Procedures information.

Refer to the appropriate wiring information.

In most cases, any problem involving continually sounding horns can be quickly alleviated by removing the horn
fuse from the Integrated Power Module (IPM).

WARNING: DISABLE THE AIRBAG SYSTEM BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, SEAT BELT TENSIONER, SIDE AIRBAG, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. DISCONNECT AND ISOLATE THE BATTERY NEGATIVE (GROUND) CABLE, THEN WAIT TWO MIN-
UTES FOR THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE BEFORE PERFORMING FURTHER DIAGNO-
SIS OR SERVICE. THIS IS THE ONLY SURE WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE TO TAKE
THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE
PERSONAL INJURY.

DR/DH

HORN SYSTEM - SERVICE INFORMATION

8H - 19