My TL has started getting the usual problem of paint peeling off the end caps of the roof racks, due to oxidisation of the aluminium. Did lots of searching, but couldn't find any reference to how these cap sections are held on? Are they just clipped on, or does it need unscrewing from under the roof lining?
I've tried a little levering force, but don't want to push it too far without knowing for certain that it clips off.

Asked the same question a few weeks ago.

The caps slide off away from the bar. Don't lift at the same time, breaks the tabs apparently.
Takes a bit of force, I put a screwdriver in the gap and twisted.

My end caps are plastic covered, but it's peeling off. Underneath is plain old galvanised iron.

Once the caps are off, you will see the screws that hold the rail onto the roof. They are not mounted from underneath, so headliner does not need to be disturbed.

I'm planning to take all 4 off, clean them up, and paint. If it looks shoddy that way, there is always 3M fake carbon fibre wrap. lol

They are acuatlly alloy for the genuine ones, they are coated similar to the wiper arms, are very hard to get good ones although I have several lol