SUPPORT AS 7I5493 - Caterpillar

Rework Procedure
Heater/Air Conditioning Unit Rework Procedure:
This Rework Procedure is for removal of the 3742088/">374-2088 Harness Assembly. A new 3742088/">374-2088 Harness Assembly, engineering change 02, must be installed. The 3742088/">374-2088 Harness Assembly is located on the heater/air conditioning unit. The heater/air conditioning unit is located behind the cab seat, underneath the heating duct work.
The new 3742088/">374-2088 Harness Assembly has an additional connection for the 3381942/">338-1942 Control Group Module (compressor protection unit).
The 3381942/">338-1942 Control Group Module will need to be installed. The 3381942/">338-1942 Control Group Module was not installed during assembly.
1. Inside of the cab, move and tilt the seat as far forward as possible.
2. Remove the heater ducts in the rear of the seat in order to allow for access to the bolts that hold in the duct work.
3. Remove all of the duct work and plates in order to access the heater/air conditioning unit.
4. Locate the heater/air conditioning unit. Refer to Image1.2.1.
Image1.2.1
5. Note the routing of the original harness on the unit. The harness is to be removed and replaced with the new harness. Refer to Image1.3.1.
6. Remove one connection at a time and replace with the terminal on the new harness. This will ensure that the terminals do not get mixed up.
Image1.3.1
7. Remove the two cover plates (six bolts) on the top of the heater/air conditioning unit in order to gain access to the wiring harness connections. The wiring harness connections are located inside of the unit. Refer to Image1.4.1.
Image1.4.1
8. Remove the bracket with the wiring connectors. Replace the old harness assembly with the new 3742088/">374-2088 Harness Assembly. Ensure that the wires go to the same connectors. Refer to Image1.5.1.
Note: Pay special attention to position of 515-EE9 and 515EE15 Grey wires. Ensure they attach to the same connectors as the old harness.
Image1.5.1
9. Replace the bracket and cover plates. Refer to Image1.6.1.
Image1.6.1
10. Continue to remove and install the harness, substituting the old connections for new.
Note: Ensure that the two white connectors 567-EE19 and 567-EE26 are installed correctly. Refer to Image1.7.1. These connectors can easily be installed incorrectly. Ensure that the correct wire number goes to the correct terminal as per the old harness that is being removed.
Image1.7.1
11. Install the 3381942/">338-1942 Control Group Module (compressor protection unit). The 3381942/">338-1942 Control Group Module is the black unit shown in Image1.8.1. The 3381942/">338-1942 Control Group Module is installed on the top cover plate of the heater/air conditioner body. The extra plug from the 3742088/">374-2088 Harness Assembly connects to this control group module.
Image1.8.1
Image1.8.2
12. Remove the relay with the following wire pin outs. Refer to Image1.9.1.
pin 30 124 Green
pin 85 220 black
pin 87 554 pink
pin 86 567 white
13. Tape over the relay base to seal it off.
Note: Failure to remove the relay will allow the compressor to run constantly.
Image1.9.1
14. Replace the cab duct work and panels.
15. Check for correct operation of the heater/air conditioning.