Hi Barnoldky,
Welcome to Apple Support Communities.
We understand that the radio inside your Ford F150 automatically switches from Sirius XM to Apple CarPlay. Is that correct? If so, we recommend you try the steps in the link below.
If you need help with CarPlay
To perform the above troubleshooting actions recommended by the article, please read through and complete steps one through seven.
We’re recommending the steps above because they directly address the issue you initially reached out to the community about, which is that the radio inside your truck automatically switches from Sirius XM to Apple CarPlay.
If the original problem persists after trying our suggested troubleshooting steps, provide us with specifics on what you see for more help, and we will continue from there.
Lastly, another thing to consider is that this may also be due to the Autoplay settings in your Ford stereo menu. Check out this page from Ford that explains further - SYNC Autoplay.
Thanks for using the Apple Support Communities.
Cheers!