Back speakers or bass in speakers in truck do not work at first but

its probably from all the vape smoke

But are the tweeters working?

Try getting it up to 88mph and going back to 1996

Old speakers need to warm up sometimes. The radio needs to send that electrical signal (heat) to them.

Rev your engine a few times before driving, and it should work. If not, try revving it up to almost the redline, shutting it off, and then revving it up to the redline again

The truck is only 4 years old.

If it’s a gm with Bose high dollar amp most likely

Unless you get high-end stuff, new factory speakers sometimes do that.....paper cones and whatnot. Try revving it up