Cruise control issues.

[itchyvet]

Have a 2006 GU ST, 3 litre DI Auto Patrol fitted with a cruise control. Have been advised said cruise control is after market and not a Nissan part, therefore Nissan will not consider checking it out.
The problem is whilst towing camper, cruise contro decides to drop out whenever it feels like it. Without camper behind, it stays in longer, sometimes works perfectly, other times a regular pain in the proverbial.
Have checked for loose wires/connections without success.
Anyone got any ideas where I could get this issue looked at by someone who knows what they're doing ?

[my third 256]

is it mechanical or electrisal

[ad4x4]

Some cruise controls will drop out if your speed drops too far below the set speed. This could happen if you are loosing speed on a climb.