Test Step 1. Inspect Electrical Connectors and Wiring -807640334

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TM 9-2320-312-24-2

Troubleshooting Section

Test Step 1. Inspect Electrical Connectors

E. Start the test and listen for a click from the air

And Wiring

inlet heater relay.

Note: The air inlet heater relay is located on the

A. Thoroughly inspect the connector J501/P501 for

front left side of the engine.

the air inlet heater relay and inspect the ECM

engine harness connector J2/P2. Inspect the

Note: Do not leave the "Intake Air Heater Enable

electrical connector J648/P648 for the lamp

Test" on. Avoid unnecessary cycling of the air

of the air inlet heater and inspect the terminal

inlet heater in order to prevent the battery from

connections on the air inlet heater relay. Refer

discharging. The "Intake Air Heater Enable Test"

to Troubleshooting, "Electrical Connectors -

has a one minute timer in order to disable the test

Inspect" for details.

when the time expires.

B. Perform a 45 N (10 lb) pull test on each of the

Expected Result:

wires in the ECM connector that are associated

with the air inlet heater (terminal 8).

Result 1 The lamp and the relay activate.

C. Check the ECM connector (allen head screw) for

Result 2 The lamp and the relay activate. The air

the proper torque of 6.0 Nm (55 lb in).

inlet heater is still suspect.

D. Check the harness and wiring for abrasion and

Result 3 The lamp activates but the relay does not

for pinch points from the sensors back to the

activate.

ECM.

Result 4 The lamp does not activate.

Expected Result:

Results:

All connectors, pins and sockets should be

completely coupled and/or inserted and the harness

RESULT 1 The lamp and the relay are

and wiring should be free of corrosion, abrasion

functioning normally. STOP.

or pinch points.

RESULT 2 Proceed to Test Step 3.

Results:

RESULT 3 There is a problem with the relay

OK Proceed to Test Step 2.

circuit. Proceed to Test Step 4.

Not OK

RESULT 4 Proceed to Test Step 5.

Repair: Perform the following repair:

Test Step 3. Check the Voltage at the

Relay Contacts for the Air Inlet Heater

Repair the connectors or wiring and/or replace

the connectors or wiring. Ensure that all of the

seals are properly in place and ensure that the

A. Turn the ignition key switch to the OFF position.

connectors are completely coupled.

B. Disconnect the wire from the relay terminal of the

Verify that the repair eliminates the problem.

air inlet heater to the air inlet heater.

STOP.

C. Fabricate two jumper wires with Deutsch sockets

on one end and Deutsch pins on the other end.

Test Step 2. Use the "Intake Air Heater

Strip a small amount of insulation from the middle

Enable Test" to Check the Circuit

of one jumper wire.

A. Turn the ignition key switch to the ON position.

B. The lamp for the air inlet heater should illuminate

for two seconds. The lamp for the air inlet heater

should shut off.

C. Connect the electronic service tool to the cab

data link connector.

D. Go to the "Intake Air Heater Enable Test" on the

electronic service tool.