Hello, I have a 2004 XJR. The boot (trunk) wont open when the weather gets past 20C or so. The actuator engages when i press the button but its not enough to release it. I can only open it by inserting the key. It closes fine and opens normally in colder temperatures. Any recommendations?

 

The actuator is getting weak and failing.
Actuators are expensive and hard to find.

 

You didn't say if lubrication was tried.
In some cases pressing down hard on the boot will assist in releasing it. Takes some pressure off the mechanism.
(I've tested that, though for an experiment not in earnest)

 

Mine's the same way, 2007. Fully releases only when cold, which isn't that often where I live. I haven't figured that it's a multi-hundred-dollar priority, so I use the key.

When I got the car it didn't even release when cold, and I spritzed it with some of this stuff recommended by a buddy. I thought it was fixed, but when it warmed up outside, it was back to the key.