I have 2017 xf 35t and I was wondering if possible my model didn't come with the feature. I have the checked flag on console but when I push the buttons nothing changes for the dynamic mode or eco mode.
cluster lights dont turn red , I've held button down for more than 3 secs. I've watch videos and gone thru the steps but nothing changes.

 

Standard feature for your car. Sounds like something is malfunctioning. Can you go into the program and adjust the variables like steering response, throttle response, shift points, suspension dampening etc.?

 

I could not tell from your post if you were pushing on the "buttons that have the icons on them or were you using the Arrow buttons on the sides to change the selection. I know "is it plugged in?" is a silly question, but sometimes it is the solution as well.
I had a question on here about the "mix" function of the USB audio. It was here for a month before I figured it out and posted the solution. I was then told, that they thought "everyone knew that". But I didn't. Sometimes the solution is obvious to others and a face palm moment for the one looking for a solution. Hope this is the solution for you.

 

You need to press the arrows, not the buttons.

 

Yes I pressure arrow button, the center section that has the checker flag and car and eco isn't really a button. The 4 little light indicator above it doesn't even light up so might be unplugged under the console

 

Yes I pressure arrow button, the center section that has the checker flag and car and eco isn't really a button. The 4 little light indicator above it doesn't even light up so might be unplugged under the console

 

The checkered flag works for my dynamic mode. Also when I am in Sport mode I can do the Dynamic mode as well.