Repair station of some sort. I think the tutorial is under transportation then "personal cars" which covered repairing vehicles.

You need second repair station or to pull them out to depot and force manual repair. To be fair it should also work for vehicle serving somewhere.

This part of the game either has not been tested very well or it needs explaining, I tried all things from moving trucks etc to a depot next to a repair centre and building a 2nd RC next to an existing one and my working trucks from the repair centre never get repaired

Also it says open hull trucks will travel to repair ..... you cant buy open hulls

I haven't had any problems with my repair station vehicles not getting repaired. Have you tried checking the box about letting vehicles be repaired inside the building itself? What about having a second truck in the same station? Perhaps the second one will 'visit' the repair station to repair the other working vehicle. Not sure though, never had any problem like this.

Yes box is ticked so ??

I doubt it can repair vehicles in building of origin. Just as DO can't bring fuel to itself of firestation extinguish fire in own building. What happens if you pull truck to depot and click "force repair" button in vehicle window? It should drive there, get repaired and return to depot.
They drive by themselves only while on route.

Do others have this problem ?

Originally posted by Oldhip:

Do others have this problem ?

No, but I usually have multiple services around the map and in larger cities there are more of them, so they are ok. Also repairing 100% damaged vehicle is available only in adjacent depot, my services didn´t like to repair such wrecks elsewhere sometimes (probably due to longer queue, though).

Last but not least, "replace vehicle" or "automatic vehicle replacement tool" is your friend with this.