I checked, it's not the Bose that I have, just factory. Such an awesome reply LesMyer - so greatly appreciated! (Thanks to Mustard as well on the junk yard ideas for speakers.)
I think the Sirius option (no CD) is freakin' perfect. I live in rural MT, so radio barely exists here. I'm going to to investigate suggested speakers and make sure all this works.
(Sadly, the passenger side dash speaker doesn't work, but I haven't figured out why yet, so prolly have to replace.)
I really would like a setup with some bass with a Bazooka sub like you mentioned. I always have the seats laid down in the back since it's just me, the wife, and the dog in the back. I'm guessing that you are using a self-amplified tube?
I'll update the post once I'm running with this...
Thanks again!

 

I have a 2001 LT 4 Door originally with single CD player and no Bose. The speakers in my dash were definitely only tweeters.

Post a photo of your RPO codes (in the glovebox) and I'll post the factory wiring schematic for your vehicle so you can see what the dash speakers are and exactly how they are wired.

My Bazooka tube is not a powered one, but I have had one before that was self-powered in my wife's previous 2008 Ranger Pickup, hooked up to the factory speaker level input with the Bazooka wiring adapter. I thought it sounded really good for a factory stereo - you could feel the sub through the seat. Why I went with another Bazooka Tube. This time I'm using a Soundstream PN5.640D 5-channel external amp hooked up to the receiver pre-outs - but I have high end Focal RSE-165 component woofers/tweeters that can utilize the power. The Kenwoods I suggested would be just fine for running off the built in amp in the receiver and will sound better than factory. Much better than factory with the sub. It all becomes a matter of how much you want to pay and what your expectations are for rocking out!

If you want to add the Bazooka tube, check their web site and see if they have a wiring harness to add a powered sub to existing factory wiring. Then you would be cutting nothing of original wiring and it should be plug n play (including power to the sub)

 

Mine's a 2001 LS 4 Door - single CD player, Delco stereo (no Bose) system. I'll attach the RPO codes from the glove box, I think they are legible.
Talked to Crutchfield yesterday and the guy there said I should disconnect the tweeters in the dash. (I'm still not sure what's there as I haven't pulled the grills.) Maybe you can enlighten me with these codes.

I'm going with that Kenwood for sure:
https://www.crutchfield.com/p_113KMX704/Kenwood-Excelon-KMM-X704.html
And the SiriusXM Rig ($69):
https://www.crutchfield.com/p_220SXV...0V1-Tuner.html

Still debating on the door speakers...
Those Kenwoods you recommended ($39):
https://www.crutchfield.com/p_113166...KFC-1666S.html
Or the Infinity speakers they recommended to me ($99):
https://www.crutchfield.com/p_108R65...EF-6532ex.html
There's also these Kickers ($69):
https://www.crutchfield.com/p_206DSC...43DSC6704.html
I might do one set of Infinity's in the front and the Kenwoods in the back (Or vice versa). Supposedly the Infinity's do a better job with bass.

Later on, I'll add something like this 125 Watt powered woofer ($169 + $39.98 wiring):
https://www.crutchfield.com/p_777B8P...ce-B-8PTD.html

But for now, I'll be happy to have music in the truck again!

Here's those codes:

 

The CD radio you indicated that you had was not original to your Blazer. The UL0 RPO code is for a cassette player version. Someone must have switched it in to have a CD player.

Here's the wiring diagrams and pinouts, and connector end views and RPO codes for the Entertainment options. Good luck and best wishes. Let us know how it turns out!

Where are you in relationship to Glacier National Park? We vacationed there about 5 years ago. Rented a small house on VRBO about 10 miles away from main park entrance for 5 days or so. We thoroughly enjoy our national parks.

Les

 

I'm not sure from those diagrams on what I have under those grills on the dash!
Totally weird about the UL0 RPO code for the cassette player. This truck has barely 100,000 miles on it, and I've had it since a bit over 80,000. Who knows, they must have done it at a dealer since it is the Delco stock stereo. Might explain some issues...
I'll pull the grills on the dash when I install this stereo rig and let you know what I find. Still might talk to Crutchfield about putting in a couple tweeters there, but the guy I talked to had owned a 2000 Blazer and was adamant about those tweeters. (He was super knowledgeable.)
Thanks so much for the help, LesMyer! I'll update you when I get this new system installed. I was seriously lost, but that Kenwood system and just reminding me about Crutchfield changed the game for this project. My wife is going to be so stoked once a SiriusXM system is booming in her Blazer...

As far as relationship to Glacier Park...
I'm a ways away now from the entrance to Glacier - used to live close to it in Whitefish and Kalispell for years. Many great times in Glacier. Not sure if you rented on the West or East side of Glacier, but both are beautiful. I'm more of a West Glacier guy, since that's where I've lived.
I live up in a hidden corner of MT now about 120 miles from the park in the Cabinets. Still freakin' beautiful here, though!
Thanks again for the help, I'll update next week...

 

Just be aware that the tweeters in the dash have a crude crossover built into the wiring to the speaker (IIRC - you can see a resistor). Personally, I would just make sure they work and leave them hooked up. That is the way my Blazer came to me. Stock radio, 4 Kenwood speakers in the doors, and factory tweeters in the dash hooked up and working. Then I put my first Kenwood unit in (an even earlier model of same receiver w/CD) and ran all off the in-receiver amp. Didn't sound bad at all. Of course you should do whatever you think is best - it's your vehicle. It's my opinion that if you add different tweeters, you should install the corresponding crossovers.

We stayed at a Columbia Falls address. So West Glacier it was. But we visited across the entire park up to Many Glaciers. Did a couple of hikes one of which included two boat rides across two lakes before the hike and ended up pretty close to some glaciers. Here's a couple of my favorite photos from that trip. Now I'm going to close this thread. Start a new one when you get it installed.

When my wife gets frustrated with local idiots for any number of reasons - she always says I'm sick of people, we're moving to Montana!

My Nose Tree photo - on hike to Avalanche Lake - screen background on my cell phone for years.


Saint Mary Lake in East Glacier - my screen background on a PC for years.

 

So how did ot turn out?