Found it myself in the US manual , its not in the UK one as far as I can see..
Anyway , for anyone whos intrested...
c The hill descent control may not control
the vehicle speed on a hill under all load
or road conditions. Always be prepared
to depress the brake pedal to control
vehicle speed. Failure to do so may result
in a collision or serious personal
injury.
CAUTION
When the hill descent control system operates
continuously for a long time, the
temperature of the brake pads may increase
and the hill descent control system
may be temporarily disabled (the indicator
light will blink). If the indicator light does
not come on continuously after blinking,
stop using the system.
The hill descent control system is designed to
reduce driver workload when going down steep
hills. The hill descent control system helps to
control vehicle speed so the driver can concentrate
on steering the vehicle.
To activate the hill descent control system:
c the automatic transmission selector lever
must be in forward or reverse gear,
c the 4WD switch must be in the 4L position
and the vehicle speed must be under 15
mph (25 km/h) or
c the 4WD switch must be in the 4H position
and the vehicle speed must be under 21
mph (35 km/h), and
c the hill descent control system switch must
be ON.
The hill descent control indicator light will come
on when the system is activated. Also, the
stop/tail lights illuminate while the hill descent
control system applies the brakes to control vehicle
speed.
If the accelerator or brake pedal is depressed
while the hill descent control system is on, the
system will stop operating temporarily. As soon
as the accelerator or brake pedal is released, the
hill descent control system begins to function
again if the hill descent control operating conditions
are fulfilled.
The hill descent control indicator light blinks if the
switch is on and all conditions for system activation
are not met or if the system becomes disengaged
for any reason.
To turn off the hill descent control system, push
the switch to the OFF position.
For additional information, see ?Hill descent control
system on indicator light? earlier in this section
and ?Hill descent control system? in the
?Starting and driving? section of this manual.