Volvo VNL 780 Operator's Manual page 103

INSTRUMENTS AND CONTROLS 93
15. Engine Brake Mode Select (ISX)
For more information about the engine brake, see "Volvo Engine Brake (I-VEB)" page 304.
OR
W3002303
I-Shift Hill Start Assist
For more information on this feature, please refer to the I-Shift Transmission Manual
supplied with your vehicle.
W3028392
OR
Optional Switch