Dodge Ram Truck 1500-2500-3500. Manual — part 412

FCM-LEFT TRAILER RELAY OUTPUT CIRCUIT OPEN (CONTINUED)

3.

FRONT CONTROL MODULE

Turn the ignition off

Measure the voltage of the Fused B+ circuit of the Trailer Tow Relay in
the IPM.

Is the voltage above 10 volts?

Yes

>> Replace the Front Control Module.

Perform BODY VERIFICATION TEST - VER 1.

No

>> Repair the Trailer Lamp Relay Output Circuit.

Perform BODY VERIFICATION TEST - VER 1.

8L - 54

LAMPS/LIGHTING - EXTERIOR - ELECTRICAL DIAGNOSTICS

DR/DH

FCM-PARK LAMP RELAY OUTPUT CIRCUIT HIGH

DR/DH

LAMPS/LIGHTING - EXTERIOR - ELECTRICAL DIAGNOSTICS

8L - 55

FCM-PARK LAMP RELAY OUTPUT CIRCUIT HIGH (CONTINUED)

For the Exterior Lighting system circuit diagram (Refer to 8 - ELECTRICAL/LAMPS/LIGHTING - EXTERIOR -
SCHEMATICS AND DIAGRAMS).

For a complete wiring diagram Refer to Section 8W.

•

When Monitored:
With the ignition on

•

Set Condition:
The FCM detects a HIGH condition

Possible Causes

PARK LAMP RELAY

INTEGRATED POWER MODULE

FRONT CONTROL MODULE

1.

INTERMITTENT CONDITION

Turn the ignition on.

With the DRBIII

T

, clear all FCM DTC’s.

Turn the Park Lamps on.

With the DRBIII

T

, read the DTC information.

Does the DRBIII

T

read: Park Lamp Relay Output

Circuit High?

Yes

>> Go To 2

No

>> The condition that caused the symptom is

currently not present. Inspect the related
wiring for a possible intermittent condition.
Look for any chafed, pierced, pinched, or
partially broken wires.

Perform BODY VERIFICATION TEST -
VER 1.

8L - 56

LAMPS/LIGHTING - EXTERIOR - ELECTRICAL DIAGNOSTICS

DR/DH

FCM-PARK LAMP RELAY OUTPUT CIRCUIT HIGH (CONTINUED)

2.

PARK LAMP RELAY

Turn the ignition off.

Remove and install a known good relay in place of the Park Lamp
Relay.

Do the Park Lamps operate normally?

Yes

>> Replace the Park Lamp Relay.

Perform BODY VERIFICATION TEST - VER 1.

No

>> Go To 3

3.

FRONT CONTROL MODULE

Turn the ignition off.

Remove the Park Lamp Relay from the IPM.

Remove the Front Control Module from the IPM.

Measure the voltage of the Park Lamp Relay Control circuit and ground.

Is the voltage above 1.0 volts?

Yes

>> Replace the Integrated Power Module.

Perform BODY VERIFICATION TEST - VER 1.

No

>> Replace the Front Control Module.

Perform BODY VERIFICATION TEST - VER 1.

DR/DH

LAMPS/LIGHTING - EXTERIOR - ELECTRICAL DIAGNOSTICS

8L - 57