Usage:
776D (5ER) Off-Highway Tractor;
777D (3PR),
793C (4AR) Off-Highway Trucks
Description of Change: An improved jumper harness reduces fan clutch speed sensor faults (CID 544-FMI 08) and errors occurring with the 3516B and 3508B engine controls. The harness includes a resistor that increases the amplitude of the signal that is sent from the fan speed sensor to the Electronic Control Module (ECM). It provides a more active pull-up to the fan speed signal, reducing signal problems associated with many of the faults. The jumper harness is installed between the fan's speed sender pigtail and the main engine harness. The jumper harness is 508 mm (20.00 in) long and after installation should be secured to the engine harness with tie wraps.
Adaptable To: The 143-5123 Harness Assembly is a fan clutch attachment effective with 793C (4AR261) Off-Highway Trucks and a custom fan clutch attachment effective with 776D (5ER86) Off-Highway Tractors and 777D (3PR599) Off-Highway Trucks, working with the engine control cooling fan systems. The harness is adaptable to all 776D (5ER) Off-Highway Tractors and 777D (3PR), 793C (4AR) Off-Highway Trucks. The harness is adaptable to 793B (1HL) Off-Highway Truck using the 3516B retrofit engine with ADEM-II Engine Control. The jumper harness is connected between the 126-1133 (793C) or 119-4166 (776D, 777D) Speed Sensor Group and the break-out for the fan clutch speed sensor on the main engine wiring harness.
NOTE: While the same speed sensor is used on earlier model trucks, the resister harness is not required as these trucks do not use the ADEM-II Engine Control.