COVER 5U7151 - Caterpillar

Illustration 1 g03797028
Schematic of the "Armbar/Seat Switch " Circuit
This diagnostic code is associated with the "Armbar/Seat Switch". These switches are connected to three inputs of the ECM. Two contacts are normally open. The other contact is normally closed. Wire G984-PK(Pink) is closed and wire G983-GN(Green) is open, when the Armbar is in the UP position. Wire G984-PK(Pink) is open and wire G983-GN(Green) is closed, when the Armbar is in the DOWN position AND the Seat is OCCUPIED. Wire G985-PU(Purple) is closed when the Seat is OCCUPIED and Wire G985-PU(Purple) is open when the Seat is UNOCCUPIED. Refer to Table 1.Note: If the Armbar is in the DOWN position and the Seat is UNOCCUPIED, the ECM will view BOTH circuits as open.
Table 1
Status of the "Armbar/Seat Switch" Circuit
Armbar Position Seat Status G984-PK(Pink) Circuit
J1-67 G983-GN(Green) Circuit
J2-54 G985-PU(Purple) Circuit
J2-71
Up Unoccupied Closed Open Open
Down Unoccupied Open Closed Open
Up Occupied Closed Open Closed
Down Occupied Open Closed Closed An FMI 04 diagnostic code is recorded when the status of both the inputs are grounded.The possible causes of this diagnostic code are listed below:
The "NORMALLY OPEN" signal circuit (wire G983-GN(Green)) is shorted to ground.
The "NORMALLY CLOSED" signal circuit (wire G984-PK(Pink)) is shorted to ground.
The "NORMALLY OPEN" signal circuit (wire G985-PU(Purple)) is shorted to ground.
The "Armbar Switch" has failed.
The "Seat Switch" has failed.
The ECM has failed. This is unlikely.System Response:The machine will be brought to a controlled stop. The park brake will be engaged. The implements will be locked out.Test Step 1. Check The Switches
Disconnect the negative battery cable and turn the key start switch to the OFF position.
Disconnect the "Armbar Switch" and the "Seat Switch" from the machine harness.
Connect one lead from a multimeter to contact A (wire 203-BK(Black)) of the connector for the "Armbar Switch".
Connect the other lead from a multimeter to contact B (wire G983-GN(Green)) of the connector for the "Armbar Switch".
Put the Armbar in the UP position.
Measure the resistance between contact A (wire 203-BK(Black)) and contact B (wire G983-GN(Green)). Note the resistance.
Put the Armbar in the DOWN position.
Measure the resistance between contact A (wire 203-BK(Black)) and contact B (wire G983-GN(Green)). Note the resistance.
Disconnect the lead from contact B (wire G983-GN(Green)) and connect the lead to contact C (wire G984-PK(Pink)). Note the resistance.
Measure the resistance between contact A (wire 203-BK(Black)) and contact C (wire G984-PK(Pink)). Note the resistance.
Put the Armbar in the UP position.
Measure the resistance between contact A (wire 203-BK(Black)) and contact C (wire G984-PK(Pink)). Note the resistance.
Connect one lead from a multimeter to contact 1 (wire 203-BK(Black)) of the connector for the" Seat switch".
Connect the other lead from a multimeter to contact 2 (wire G985-PU(Purple)) of the connector for the "Seat switch".
The Seat is UNOCCUPIED.
Measure the resistance between contact 1 (wire 203-BK(Black)) and contact 2 (wire G985-PU(Purple)). Note the resistance.
Occupy the Seat.
Measure the resistance between contact 1 (wire 203-BK(Black)) and contact 2 (wire G985-PU(Purple)). Note the resistance.
Table 2
"Armbar Switch" Circuit Resistance
Armbar Position A To B A To C
Up 5000 Ohms 5 Ohms
Down 5 Ohms 5000 Ohms
Table 3
"Seat Switch" Circuit Resistance
Seat Status 1