any you jokers know of a device you can use to see if your truck has gps fitted not a jammer just a detection device cheers

Well.... unless you have one of those communication systems from a carrier, like a qualcomm unit, you have GPS as part of the system. If you only have the truck as manufactured, you don't. Not sure why it is important anyway. If you are worried about someone being able to know your whereabouts, then you better make sure you ditch your cell phone, credit/debit cards, and never buy anything (including fuel) away from the house. No matter what we all think, some real hot shot attorney will be able to almost find the location you last went to the can. The government can't find its hind end most of the time, so they are the least of my concerns. But if there is an accident or other occurence that causes someone to call the law firm of Burn 'em and Run, then they are going to find out everything about you they want to.

Of course, it is a lot harder to track down the Amish. You could always use horse and wagon to haul freight.

Looks like a decent setup here (just watch out for the exhaust):

over here companies put them in ,a good idea for knowing where you are no problem with that ,but police get acess then your log book gets checked against it ,and we no wat haps then .boss ot it taken out of mates truck and told me it not in my truck ,i checked and not found 1,told they in top consel of kws

If it’s just a GPS tracker and has no transmission to a satellite or terrestrial antenna, then there would be no way to tell if there is some sort of device. If you’re talking about a system like Qualcomm, then I imagine something like a “bug detector” that you could get at a “spy shop” might do the trick.