Usage:
3126B (7AS),
C-10 (3CS),
C-12 (2KS),
3406E (2WS, 1MM) Truck Engines
Description of Change: There is a new 70-pin breakout "T" harness now available for servicing the above truck engines. These truck engines all feature a new Electronic Control Module (ECM) which has two 70-pin connectors. Previous engines used a 40-pin connector. The design and intended usage of the 70-pin breakout "T" harness is different from the previous 40-pin breakout "T" harness. The 70-pin breakout "T" harness differs from the 40-pin breakout "T" harness because it is a "partial" breakout "T" harness rather than a "full" breakout "T" harness.
The 70-pin breakout "T" harness is intended for troubleshooting with the ignition switch in the "ON" position with the engine not running. Many of the troubleshooting guide procedures are specifically written for use with the 70-pin partial breakout "T" harness. Using the breakout "T" harness helps to eliminate the need to remove wires from the engine wiring harness and the vehicle wiring harness.
Because the 70-pin breakout "T" harness is a "partial" "T" harness it has decreased noise susceptibility, is easy to install, and has a relatively low cost.
Proper use of the 70-pin partial breakout "T" harness, when used in conjunction with the troubleshooting guides, provides a great deal of flexibility in troubleshooting and diagnosing 3126B and 1999 model year C-10, C-12, and 3406E Truck Engines.
Adaptable To: The 140-2266 70-Pin Partial Breakout "T" harness is used on 3126B (7AS), C-10 (3CS), C-12 (2KS), and 3406E (1MM, 2WS) Truck Engines that are equipped with the ADEM 2000 ECM. Previous engines were serviced with the 7X-1715 40-Pin Full Breakout "T" harness.