How can I repair a damaged truck?
My truck is damaged badly, but I cannot figure out how to repair it. When I use it an in-game tip appears about placing it in a garage, but when I drive it to a garage I cannot enter it - the elevator turns red and says that an incorrect object is placed there.
What can I do? Are there any special garages for trucks?
You're trying to repair a MULE truck. You can't repair those.
As you follow the main story, you'll eventually unlock the ability to craft your own BRIDGES-issued trucks. Those can be repaired, and are far superior to MULE trucks in every conceivable way.