WINDOW-FRONT 3822342 - Caterpillar

Table 1
ECM Harness Codes    
Pin Number    Machine ECM
(MID 039)    LH Operator ECM
(MID 156)    RH Operator ECM
(MID 157)    
J1-26     GND     Open     GND    
J1-27     Open     GND     Open    
J1-28     Open     GND     GND    
J1-32     GND     Open     Open    Before you perform this procedure, determine the proper machine harness code. The main display module must have the correct part number for the particular machine. If the machine harness code is not shown correctly, this procedure determines the component that is malfunctioning. This failure could be caused by a failure in the main display module, an incorrectly wired harness, or a harness that has failed. Note: The harness code of each ECM is the status (open or ground) of the four harness code inputs. The connector contacts on each ECM are: J1-26, J1-27, J1-28 and J1-32. The main display module uses the harness code and the machine serial number to assign a number to the machine. This number is the machine code. The machine code is shown during machine code mode. Each sales model also has a specific machine code. The specific machine code is listed in Systems Operation, "Machine Code Mode". The specific harness code is given in the Electrical System Schematic.Note: The following procedure checks for incorrect harness codes on the inputs for the main display module. The status of the harness code is found in the test "Determine the harness code". Compare the status of the harness code to the status at the inputs for the main display module. The table identifies the connector contacts of the harness code circuits. Contacts that are specified as grounded contacts should be checked for opens in the harness. Contacts that are specified as open contacts should be checked for shorts in the harness.Test Step 1. CHECK FOR OPENS
Turn the disconnect switch to the OFF position.
Disconnect the machine harness from the main display module.
Check for continuity between the connector contacts that are specified as GROUNDED contacts and ground. Check for continuity at the machine harness connector for the main display module.Expected Result:The resistance measures 5.0 ohms or less.Results:
YES - The resistance is 5.0 ohms or less. The circuit for the harness code is not open. No defect was found in the ground circuits for the harness code. Proceed to test step 2.
NO - The resistance is greater than 5.0 ohms. The circuit for the harness code is open. The machine harness is incorrectly wired or the harness has failed.Repair: Repair the open circuits for the harness code that is found or replace the machine harness. If conditions are not resolved, proceed to test step 2.Test Step 2. CHECK FOR SHORTS
The disconnect switch remains in the OFF position. The machine harness to the main display module remains disconnected.
Measure the resistance between the connector contacts that are specified as OPEN contacts and ground. Measure the