I just noticed today that my front passenger aluminum doorsill plate is loose. Does anyone know how to remove it or tighten it back down? I don't want to pull on it and accidentally break it.

 

It'll probably be one of the clips that hold it down, might have popped off, I'd pull it completely off and have a look under see what needs fixing, you might just be able to put the clip back on and push it back into place or might need a new clip.

 

Warning - wear gloves or use a flat trim tool. Do not pull it up with bare fingers or there is a good chance you will cut them! Don't make the mistake I did!

It could be a clip, or it could be the aluminium facing coming off the plastic backing as they are only held on with double-sided tape. If the latter it will be easier to repair out of the car where you can clamp the two parts together until the new tape/glue sets.

Lift at the inner edge first until able to get your hand/tool under, then pull up from the front edge towards the back. There are some photos on another forum that show where the clips are:
Adding Illuminated Tread Plates

The white plastic ones are along the inner edge.

 

xdave your going to have to let me know how you became the fountain of all knowledge do you work for Jaguar? (off topic)

 

The clue is in the fact I cut my fingers doing it myself. I can tell you the best way to remove something because usually I've tried all the bad ways first.

I tend to buy cars to keep for a long time so I get to know them inside and out to the point that (quite sadly) I can tell you where many of the electrical modules are grounded in an X350. (That could be my Mastermind specialist subject!) If it is not welded or rivetted in place I have probably taken it off at least one of my cars at some time. I'm not one to be afraid of taking something apart and not being able to put it back together again... as my drawer full of leftover screws and bolts will tell you. Cars are really just giant Meccano sets, and after a while you learn how different parts of the cars are put together even across different models.

Although I've never worked for Jaguar, I have offered advice to local dealers when they've had customers with obscure electrical issues. In return I get to chat to the techs about issues they have seen so pick up all sorts of information that sometimes comes in useful.

Mostly though it is a case of wanting to see if I can do something. I share as much as I can because collectively we all learn from each other's progress (and the mistakes too). To use your term - online forums are the real fountain of knowledge. You can search this site and find out how to do pretty much anything to your car.

 

I added the illuminated front sill plates and it was an easy DIY job. Just pull up from the top front edge firmly and start to pop it off and continue to work your way down. Make sure all the plastic clips are in place and there are no obstructions before snapping it back in place from the bottom to the top. A few good whacks with your fist along the way helps to secure the clips.