Cruise control and environment

[JustinM5]

How the hell does it work, a switch and some wires??
On a certain stretch of road it doesn't work in 4 different lorries I use!
Is really bugging me, every week it's the same, as soon as past this road it works :confused:

[Enforcer]

Is there an incline you're going up that may cause it not to have enough oomph?

[JustinM5]

Partly uphill, but get to top speed.
Turn the CC on and off, engine on and off, just won't set the speed.
Is the B4640 from Swan Newtown to A34 Tothill services - either side of this road it works all day long!