Volvo FM Handbook page 155

144 Driving
4 Engage the differential lock between the wheels on
the rear axles.
The control lamp on the instrument panel will flash.
5 Move the front-wheel drive switch to its bottom
position.
The control lamp on the instrument panel will come
on.
Second position, differential lock in
transfer gearbox and rear axles
engaged. The axle differential lamp
flashes and the lamp for the transfer
gear comes on.
Note!
The differential lock is not engaged
until the warning lamp on the
instrument panel flashes. The
differential lock is engaged as long
as the warning lamp is flashing,
even if the switch is turned off.
J4017790
J4015829