Test Step 2. Check the Programming of the "Fan Control Type" Parameter -807640393

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TM 9-2320-312-24-2

Troubleshooting Section

Verify that the repair eliminates the problem.

Expected Result:

The status of the A/C high pressure switch indicates

STOP.

ON or OFF.

ECM not wired to fan or switch If the ECM is not

wired to the cooling fan on the vehicle and/or the

Results:

A/C high pressure switch, then the ECM is not

Yes The status of the A/C high pressure switch

being used for fan control. STOP.

is ON or OFF. Proceed to Test Step 4.

Test Step 2. Check the Programming of

the "Fan Control Type" Parameter.

No The status of the A/C high pressure switch

is "Unavailable". The ECM is not programmed

to use the A/C high pressure switch. Proceed to

A. Connect ET to the cab data link connector.

Test Step 5.

B. Check the "Fan Control Type" parameter. Ensure

Test Step 4. Use ET to Check the

that the parameter is programmed to"On-Off",

Operation of the A/C Pressure Switch.

if the ECM is used to control the fan. If the

parameter is programmed to "None" and the

A. Connect ET to the cab data link connector.

ECM is connected to the fan, then the fan will

always be ON.

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

Expected Result:

C. Access the "A/C High Pressure Switch" status

screen on ET.

The "Fan Control Type" parameter is programmed

to match the vehicle wiring. This is determined in

D. Fabricate a jumper wire 100 mm (4 inch) long.

the previous step.

Crimp a Deutsch pin to both ends of the wire.

Results:

E. Disconnect the "A/C High Pressure Switch" from

Yes Proceed to Test Step 3.

the vehicle harness at the switch and use the

jumper wire to short the two terminals in the

harness connector together.

No Program the "Fan Control Type" to the

correct setting and then recheck the system. If

F. Remove the jumper wire and then insert the

conditions are not resolved, then proceed to Test

jumper wire. At the same time, view the "A/C

Step 3.

High Pressure Switch" status on the service tool

Test Step 3. Use ET to Check the A/C

status screen.

Pressure Switch.

Expected Result:

A. Connect ET at the cab data link connector.

The status screen indicates that the "A/C High

Pressure Switch" is turning to the ON position. Then,

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

the "A/C High Pressure Switch" is turning to the

OFF position.

C. View the following Customer Specified

Parameters.

Results:

"Fan Control Type"

Yes The A/C high pressure switch harness is

OK. Proceed to Test Step 6.

"A/C Switch Fan On-Time"

No Proceed to Test Step 7.

Ensure that the "A/C Switch Fan On-Time" is

programmed to a greater value than "0". If the

Test Step 5. Use ET to Check Active

"A/C Switch Fan On-Time" is programmed to

Codes or Logged Codes.

"0", then the "A/C High Pressure Switch Input"

(Input 11) is not used.

A. Connect ET to the cab data link connector.

Note: If the "Fan Control Type" parameter indicates

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

"None", then the cooling fan driver is not used.

C. Access the "Logged Diagnostic Codes" and the

View the "A/C High Pressure Switch" status on

"Active Diagnostic Codes" on ET.

ET.

D. Check for the following diagnostic codes.