Dodge ram truck 3500 1996 Service Manual page 245

B R
BRAKES 5 - 61
D I A G N O S I S AND T E S T I N G ( C o n t i n u e d )
RWAL DIAGNOSTIC PROCEDURES—TEST 4
This test has only the brake warning lamp illumi­
nated. Except for the parking brake switch, all other
brake warning lamp switched ground circuits will
cause the ABS warning lamp to illuminate also. This
test verifies whether the parking brake switch is the
only cause for brake warning lamp illumination or
there is a malfunction with the ABS warning lamp
circuit.
Step Action Yes
No
1
Turn the ignition key OFF Turn the ignition key to
the RUN position. • Did the ABS warning lamp
illuminate for a few seconds and then extinguish?
Perform step 2
Perform step 6.
2 Release the parking brake.
e Did the brake warning lamp extinguish?
System is operating
normally
Perform step 3.
3 Pull the parking brake release handle and pull the
parking brake pedal upward. Verify the operation of
the parking brake mechanism.
© Were you able to pull the pedal up any higher?
Perform step 4. Perform step 5.
4 © Did the brake warning lamp extinguish when the
parking brake was released fully?
Repair the parking
brake system as
necessary.
Repair the parking
brake system as
necessary then,
perform step 5.
5 Turn the ignition key to the OFF position. Disconnect
the CAB 14-way connector.
WARNING: NOTE: Vehicles with diesel engines
must also have the vacuum sensor
disconnected.Turn the ignition key to the RUN
position.
• Is the brake warning lamp illuminated?
Repair the brake
warning lamp ground
control circuit for a
short to ground and
perform the Verification
Test.
Replace the CAB and
perform the Verification
Test.
6 ® Is the ABS warning lamp illuminated continuously? Perform RWAL
DIAGNOSTIC
PROCEDURES TEST
1.
Perform step 7.
7 Inspect the CAB 14-way connector.
© Is the connector properly connected to the CAB?
Perform step 8
Reconnect and perform
the Verification Test.
8 Inspect the wiring and terminals at the connector.
© Are the terminals or wiring pushed out or
damaged?
Repair as necessary
and perform the
Verification Test.
Perform step 9.
9
Connect an ohmmeter to terminal 10 and a good
chassis ground.
© Is the resistance to ground less than 1 ohm?
Perform step 10
Repair the ground
circuit and perform the
Verification Test.
10
Connect a voltmeter to terminal 2 and a good
chassis ground. Turn the ignition key to the RUN
position.
© Is the voltage less than 9 volts?
Perform step 11. Replace the CAB and
perform the Verification
Test.
11 Inspect the ABS warning lamp bulb.
© Is bulb functional?
Repair the open circuit
from terminal 2 to the
ABS warning lamp and
perform the Verification
Test.
Replace the bulb and
perform the Verification
Test.