Usage:
Installation of a 1991 3176...7LG Truck Engine into a chassis wired for a 3176 ...2YG Truck Engine requires an adapter wiring harness. If the engine is equipped with a Jake Brake ®, a solid state relay control is also required.
A 4P5880 Adapter Wiring Harness adapts the 40-pin Deutsch connector on the 1991 engine to the two 9-pin Deutsch connectors on the OEM wire harness. Once installed, the adapter wiring harness must be secured using tie straps.
NOTE: A 4P5881 Adapter Wiring Harness is also available for installation of a 3176 ...2YG engine into a chassis wired for a 3176...7LG engine.
If the engine is equipped with a Jake Brake, the 2YG pulse width modulated (PWM) Jacobs electronic control must be replaced with a solid state relay control. The 1991 7LG Electronic Control Module (ECM) supplies a 12V signal to apply the Jake Brake instead of the 2YG PWM signal. All components necessary for installation are included in Jacobs part number 017596 Solid State Relay Group (if equipped with an Anti-lock Braking System use a 017597 Solid State Relay Group). The 017596 Solid State Relay Group consists of the parts listed in the chart.
If equipped with a Jacobs Dash Module (touch control) the entire 017596 Solid State Relay Group is required. However, if already equipped with manual dash control switches, the necessary components can be purchased separately (see chart). Refer to the illustration for the solid state relay control wiring diagram. Use of the Jacobs color coded wiring harnesses will ease installation. If necessary, reference Jacobs part number 015851D "Installation Manual for Models C317 and 317A Engine Brakes " for detailed installation instructions.
NOTE: Correct grounding is important. If the Jacobs control ground is questionable, run the green ground wire directly to the engine cylinder head ground stud.
C-317A Wiring Diagram.