Recently I have noticed in our Rendezvous that occasionally the front speakers will cut in and out while driving, and then when you turn off the radio they will still buzz and crackle intermittently. Is this an amplifier issue, or should I test the wiring at the amp, too?

Thanks!

if you have uq3 in the rpo list then there is a amp. in that case if you have more than one normally its the amp. not to say its impossible to have two bad speakers though it would be helpful if you had a known good speaker and try it in the bad spot, say if your back ones are the same size swap one and see if the issues move

do all the speakers crackle or just the fronts

It is just the front woofers and tweeters. Today they just didn't work (no sound, no crackling), and then they would work again for about a minute or two, and then they would all stop working again, and sound would just come from the rears.

try to swap a back one for a front one. if its still messed up its likely the amp

Pretty unlikely that all the front speakers would fail at the same time like that... and a "blown" speaker doesn't usually just quit working anyway, it just sounds distorted and muddy.

Another vote for amplifier if you have one, or if not then the head unit itself (actually the amplifier within in).