Addition Of Two Wires To The Engine Wiring Harness Assembly At Overhaul Caterpillar

Addition Of Two Wires To The Engine Wiring Harness Assembly At Overhaul

Usage:

OFF-HIGHWAY TRUCKS793C (4AR, 4GZ) OFF-HIGHWAY TRUCKS

Problem:

The original 137-8260 Engine Wiring Harness Assembly for the above trucks included all the necessary wiring to connect the engine to the chassis wiring. The former 137-8260 Engine Wiring Harness Assembly has been canceled and replaced by the new 153-7490 Engine Wiring Harness Assembly. This new wiring harness assembly includes several improvement. But, the 153-7490 Engine Wiring Harness Assembly also includes the removal of the two wires for the Transmission Charge Filter Switch that were a part of the former 137-8260 Engine Wiring Harness Assembly.

At the same time the Transmission Charge Filter Switch wires were removed from the engine wiring harness, these wires were added to the 145-4389 Front Chassis Wiring Harness Assembly. For those 793C engines built with the 137-8260 Engine Wiring Harness Assembly that are now receiving an engine overhaul that includes a new 153-7490 Engine Wiring Harness Assembly, but the chassis is not receiving a new front chassis harness, two wires need to be added to the 153-7490 Engine Wiring Harness Assembly for the Transmission Charge Filter Switch.

Solution:

Use the following procedure to add two wires to the 153-7490 Engine Wiring Harness Assembly:

1. Add a wire, 2.150 meters long, to replace the nonexistent 426 wire. Connect a 003-9834 Protector and a 131-1475 Terminal Assembly to one end of this wire. Connect this end to the Transmission Charge Filter Switch.

Connect a 8T-8729 Pin to the other end of this wire. Connect this end of the wire to Pin 38 of the Machine Interface at the left rear corner of the engine.

2. Add a second wire, approximately 2 meters long, to replace the nonexistent 201 VIMS ground wire. Connect a 003-9834 Protector and a 131-1475 Terminal Assembly to one end of this wire. Connect this end to the Transmission Charge Filter Switch.

Splice the other end of this wire into the 201 wire (VIMS ground) behind Pin 2 of the Machine Interface at the left rear corner of the engine.

At some point in the near future, the engine wiring harness will come with the two wires for the Transmission Charge Filter Switch. For those trucks that include the Transmission Charge Filter Switch wires as part of the chassis wiring harness, tape off any unused Transmission Charge Filter Switch wires that are a part of the engine wiring harness.