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2002-2009 Chevrolet TrailBlazer

How to upgrade the stereo system in your TrailBlazer

Chevrolet TrailBlazer

In brief: This Crutchfield Research Garage article gives you an overview of your TrailBlazer's stock stereo system and your aftermarket upgrade options. We'll tell you all about:

Then, use our vehicle selector to find the gear that will fit your TrailBlazer.

Overview of the Chevy TrailBlazer

When the TrailBlazer debuted in 2002, Chevy was still using their long-running "Like a Rock" ad campaign. And with big, comfy vehicles like this one, the theme was appropriate. The TrailBlazer, like most GM trucks and SUVs of the era, offered a solid engine, a solid chassis, solid looks, and solid value. Used TrailBlazers still do, if you happen to find a nice one.

The TrailBlazer was available in "Regular" or the stretched EXT model, which seated seven people in reasonable comfort. Performance-oriented customers could choose the Corvette-motored SS model starting in 2006. As the first SUV to carry Chevy's legendary Super Sport designation, it accelerated, turned, and stopped way better than a large, truck-based SUV had any right to.

That's the one we'd want, but if you need a solid mid-sized SUV for everyday duties, any TrailBlazer is a pretty sharp choice. A new stereo will add great sound and up-to-date functionality to your fun family hauler.

chevy trailblazer navigation radio

The optional nav receiver can be replaced by a variety of newer models (Crutchfield Research Photo)

The TrailBlazer's factory stereo system

The factory stereo systems are, like most factory stereo systems, pretty dull. The Bose® system was a distinct improvement over the base model, but it's still getting on in years and you can do better. A healthy number of single-DIN (2" tall) and double-DIN (4" tall) stereos will fit right in, with the help of a dash kit that's designed specifically for your TrailBlazer.

Depending on the receiver you choose, you may have to unbolt or cut out the factory radio's rear support bracket to create the space necessary for the new receiver. That info will be presented to you before you buy anything, so don't stress. If you do need to deal with the bracket, that's not worth stressing about, either. It's not a structurally important piece and it's not that hard to remove.

chevy trailblazer dash cavity

You'll need to remove this bracket to install a new receiver. It's not as hard as you might think. (Crutchfield Research Photo)

The TrailBlazer's audible safety alerts (aka "warning chimes") are delivered through the factory radio. You'll need an adapter that retains the factory warning chime (plus OnStar) and provides a switched 12-volt power source for your new radio. Crutchfield strongly recommends that you use the recommended adapter when you replace your radio. The adapter isn't free, but when you purchase it along with your new receiver, we'll give you a very nice discount off the retail price.

You'll also need an antenna adapter and a wiring harness adapter that will allow you to connect the new radio without having to cut into the factory wiring. All of those items are available at a healthy discount, too, and you'll also get a free Crutchfield MasterSheet, which contains illustrated, step-by-step instructions on how to install a new stereo and speakers in your truck.

chevy trailblazer base radio cassette

The base radio had a cassette deck, which you really don't need anymore, right? (Crutchfield Research Photo)

Removing the factory radio in your TrailBlazer

Before you do anything else, set the truck's parking brake and disconnect the negative battery cable to prevent any electrical shorts. Once everything's secure, you'll start by removing two 7mm screws from the driver’s knee panel. There may or may not be screw covers over them, but if there are, you can remove them by gently popping them off with a screwdriver. Either way, once the screws are removed, you can pry out the top edge of the knee panel and release the retaining clips. It's okay to just let the panel hang while you're doing everything else you need to do.

The rest of the process is pretty straightforward. Remove three Phillips screws from the bottom of the dash trim panel that's exposed by lowering the knee panel. Next, remove one Phillips screw, located to the left side of the 12 volt power outlet, from the dash trim panel. Then you'll remove two more Phillips screws from just above the instrument cluster.

Detailed stereo and speaker removal instructions

MasterSheet image
With step-by-step disassembly instructions and plenty of up-close, detailed photos, our exclusive Crutchfield MasterSheet™ takes the guesswork out of removing the factory stereo and speakers. It's free with your Crutchfield order, or you can purchase one separately for just $9.99.

Place the steering wheel in its lowest position, then carefully pry around all edges of the dash trim panel to release six retaining clips. Disconnect the wiring harnesses and work the dash trim panel over the steering column until the panel's out of the way.

With that, all you need to do is remove the three 7mm screws securing the factory radio, disconnect everything, and set it aside. Secure the new receiver to the mounting bracket following the instructions included with the bracket, make your wiring connections, then install the stereo. Test it out to make sure it's working and, if it is, start putting the dash back together.

Tools needed: Phillips screwdriver, panel tool, 7mm socket, ratchet & extension

Read our Car Stereo Buying Guide for shopping tips and advice.

Shop for car stereos that fit your Chevrolet TrailBlazer

Steering wheel audio controls

In most cases, it's reasonably easy to retain your SUV's steering wheel audio controls when you install a new stereo. When you enter your vehicle information, our database will choose the adapter you need to make your factory steering wheel controls work with a compatible aftermarket receiver.

chevy trailblazer front door speaker

The front door speakers vary, depending on whether you have the base or the Bose system. This is a Bose speaker. (Crutchfield Research Photo)

Removing the factory speakers in your TrailBlazer

All TrailBlazers, including the EXT, have factory speakers in the dash, front doors, and rear doors.

chevy trailblazer dash tweeter

The corner dash tweeters aren't hard to replace, but you'll need to pay attention to what you're doing (Crutchfield Research Photo)

Replacing your TrailBlazer's dash corner speakers

Bose-equipped trucks feature tweeters underneath grilles on the far left and right sides of the dash. If you want to replace these tweeters, you'll need to remove the A-pillars and the top dash panel.

This isn't hard to do, but the airbag assembly is located behind the dash trim panel, so be very careful when you're doing this. Another reason to be careful (but a less-urgent one) is that you don't want to damage the panels.

There are no mounting brackets or wiring harnesses available for these speakers, so you'll need to use our universal backstraps (or silicone or hot glue) to hold them in place and Posi-Products connectors to connect your new tweeters to the factory wiring.

Your new speakers might not include mounting screws, so check the box before you start. If you have to make a run to the hardware store, it's obviously best to do it before you take your dashboard apart.

Tools needed: Phillips screwdriver, flat blade screwdriver, panel tool, 7mm socket, ratchet & extension

chevy trailblazer front door

You have plenty of options when you're replacing the TrailBlazer's front door speakers (Crutchfield Research Photo)

Replacing your TrailBlazer's front door speakers

The TrailBlazer's standard front speakers are 4-ohm 6-3/4" units, while the Bose-equipped models contain 8" 2-ohm speakers. Both varieties can be replaced with a wide variety of aftermarket speakers, though you will need mounting brackets to install smaller speakers in bigger cavities. They're included at a deep discount with your Crutchfield speaker purchase.

You'll need to remove the door panel to access these speakers, but that's a straightforward process, and it's all explained in your Crutchfield MasterSheet.

Standard speakers

The standard 6-3/4" woofer is a component piece with a tweeter just above it. The woofer receives a full-range signal, so you can ignore the tweeter and swap in a new full-range speaker. You could also install new component speakers here pretty easily.

You can use the factory brackets and grilles with your new speakers, but you may need to grind off some material to get a perfect fit. You'll also have to remove the locating tabs from the factory speaker bracket before mounting a new speaker or bracket. Just use a pair of pliers to snap them off. Don't worry about the bracket — this minor tweak won't affect the structural integrity.

Bose speakers

In the Bose system, the factory front door speaker is a woofer that receives a low-pass signal from the factory amp. When you install an aftermarket speaker, you'll only get bass unless you bypass the factory amp, which is located in the right rear cargo area.

Once you're done installing your speakers, test them out to make sure they're working properly. And before you reinstall the door panel, make sure the speaker wires aren't interfering with the windows and test the door lock and release operation.

Tools needed: Panel tool, 10mm and 1/4" sockets, ratchet & extension, Torx T-15 driver, pliers

chevy trailblazer rear door speaker

Replacing the rear door speakers is pretty much the same as replacing the front door speakers (Crutchfield Research Photo)

Replacing your TrailBlazer's rear door speakers

Replacing the rear speakers in your TrailBlazer is basically a lot like replacing the ones up front. You'll need to remove the door panels, of course, being careful not to damage the sometimes-snug plastic retaining clips.

As with the front speakers, you'll use a pair of pliers to break off the line-up tabs on the factory speaker bracket. This will allow your new speaker to fit flush against the bracket. You may also need to break off the three square mounting tabs on the speaker/bracket assembly.

Depending on your TrailBlazer's year and factory equipment, everything from 5-1/4" to 6-3/4" aftermarket speakers will fit in the rear doors. Once you've entered your vehicle information into our Outfit My Car tool, you'll see a complete array of what's available for your truck.

Tools needed: Phillips screwdriver, small flat blade screwdriver, panel tool, 1/4" and 7mm sockets, ratchet & extension, Torx T15 driver, pliers

Read our Car Speakers Buying Guide for more information.

Shop for speakers that fit your Chevrolet TrailBlazer

Chevy Trailblazer cargo area

There's plenty of room for a sub enclosure in the Trailblazer's cargo area

Bass in your TrailBlazer

Like most SUVs, "mid-size" or otherwise, the TrailBlazer has room for just about anything you want to toss into the cargo area. If you want to install a subwoofer box filled with gi-normous subs (and the amps to power them), you have a 45" W x 14" H x 34" D space to work with.

If you still use your SUV as a people-and-gear carrier, though, you'll need all that cargo space for, y'know, cargo. You can choose from a wide variety of powered subwoofers, all of which will deliver an impressive amount of thump without taking up all the space you were saving for groceries and sports equipment.

Learn more about building a bass system in our Car Subwoofer Buying Guide.

weathertech floor liners

Custom-fit floor liners will keep your TrailBlazer's interior looking sharp

Other options for your TrailBlazer

There are plenty of other ways to improve your TrailBlazer. Here are some of the ways Crutchfield can help.

Protect that carpeting

Even if your TrailBlazer isn't a work truck, your carpeting can still get pretty ratty over time. Protect it with a set of custom-fit WeatherTech floor liners. They'll keep dirt and spills contained to keep your carpeting looking pristine.

See more with a rear-view camera

With a vehicle this large, you really need to be aware of your surroundings. A rear-view camera is a big help when you're backing up in a crowded parking lot. Connect it to your nav or DVD receiver for increased awareness and safety.

Seal in sound with speaker baffles

We frequently suggest foam speaker baffles for other vehicles, but for an SUV like this, we strongly recommend them. Those big doors can waste a lot of great sound, and these rubber baffles are an inexpensive way to rein it back in. They're easy to install, and they'll give you improved performance while also protecting your speakers.

Protect your truck with a security system

Installing a security system in your TrailBlazer isn't easy (security systems usually aren't), but it's definitely a good idea. Our Crutchfield Advisors can help figure out what you need to get the job done, but we usually recommend taking your car and new gear to a professional installer.

Let's get started!

Ready to shop? Use our vehicle selector to find the gear that will fit your car or truck. If you have questions of your own, give us a shout via phone, chat, or email

  • Wayne Prejean from Jennings

    Posted on 8/30/2022

    I'm looking to change my stock stereo and speaker to to a factory Bose stereo and speakers,I have a 2002 trailblazer ls 2 wheel drive and the Bose system has come out a 2006 trailblazerltz, can you help me with this? Thanks

    Commenter image

    Jon Paul from Crutchfield

    on 8/31/2022

    Wayne, Those OEM-for-OEM swaps are rarely as easy as easy as you'd imagine. Sometimes, they don't work at all. You might be able to find some guidance on a Chevy truck owners' forum, though. If that doesn't work, we can help you find some aftermarket gear that'll sound great in your truck. Good luck!
  • Dee Grizzly from Toledo

    Posted on 4/29/2021

    Are these known to have issues with the quality of sub woofer sound? I ran 3 different set ups and it's just something off about it. Woofers are pushing and moving air like they should, and the bass hits hard enough to shake the truck. Do sound deading mats make a huge difference? Is it worth the effort?

    Commenter image

    Jon Paul from Crutchfield

    on 4/29/2021

    Dee, We haven't heard a lot of specific complaints, but if you're having issues, we can help. Sound deadening might be one possible solution, so give us a call and talk to one of our advisors. We can help you choose the right gear and give you the right advice on how to install it.
  • Michael from Pierre

    Posted on 1/9/2021

    I have a 2005 ext with the bose system. I've recently put in an aftermarket deck, subs and amp. I cannot for the life of me get the subs to put out any sound. Everything is wired correctly and works properly. I'm using a mono amp so the subs are wired correctly as well. My only idea is that the bose system amp is simply overriding the rca cables from the stereo to the amp running the subs. My only other thought to getting these subs working is to run rca cables from the sub amp to the bose amp and set the sub amp as the slave amp. Is this even close or am I grasping at straws here?

    Commenter image

    Jon Paul from Crutchfield

    on 1/11/2021

    Michael, With questions like that, it's always better to have a conversation with a real live human. If you bought your gear from Crutchfield, you can call Tech Support for free help troubleshooting your system.
  • Harry from San Diego

    Posted on 9/22/2020

    A couple of things. I used the Crutchfield prompts on which system to buy and appropriate adapters. You should be aware that the adapter comes with bare wires and splicing them in takes care and carefully following the wiring diagram. I soldered the connections which was very time consuming. The instructions were silent on connecting the new chime box so my system wouldn't boot up until I called tech. Luckily the tech immediately knew the problem and I was good to go. Finally, the biggest problem I encounter was disconnecting the various wiring harnesses. I swear everyone is different and requires a different method to unplug. I probably wouldn't gotten the rear wiper switch loose but for a lucky hit on YouTube.

    Commenter image

    Jon Paul from Crutchfield

    on 9/24/2020

    Harry, Thanks for sharing your experiences. For anyone who's reading this, we'll point out that when you buy your gear from Crutchfield, you can call Tech Support for free installation and troubleshooting help.
  • Michael Parton from Kansas city

    Posted on 9/18/2020

    I have a 2005 chevy trailblazer base model radio but I want to up grade it to a touch screen radio. What size should I get? 5 inch?

    Commenter image

    Jon Paul from Crutchfield

    on 9/18/2020

    Michael, A healthy number of double-DIN (4" tall) stereos will fit right in, with the help of a dash kit that's designed specifically for your TrailBlazer. When you enter your vehicle's info into our Outfit My Car tool, you'll see which stereos fit your truck, plus the correct harness. If you have any questions, our advisors are available via phone or chat.
  • Karen from Celina

    Posted on 9/4/2020

    You forgot to include that when you replace the radio in the Trailblazer you need to reprogram the computer to get the new one to play. Because of the anti theft security that was programmed.

    Commenter image

    Jon Paul from Crutchfield

    on 9/8/2020

    Karen, Interesting point, and, well, it depends. If you replace the stock radio with an aftermarket model and use the correct data interface, no reprogramming will be necessary. But if you're trying to replace the factory radio with a different GM factory radio, for example, that may require some programming work.

    When you enter your vehicle's info into our Outfit My Car tool, you'll see which stereos fit your truck, plus the correct harness. If you have any questions, our advisors are available via phone or chat.
  • John from French Lick

    Posted on 7/18/2020

    I have a 2004 Trailblazer. I purchased a Double Din JVC Radio and a PAC RP5-GM11 interface..I have had nothing but trouble with this install. I don't think I need that interface. It sounds like your kit is far simpler and is more designed for my Trailblazer which doesn't have On Star or Bose Sound w/amp.......

    Commenter image

    Jon Paul from Crutchfield

    on 7/20/2020

    John, Yes, you might have the wrong interface. Give us a call and talk to one of our advisors. We can help you choose the right gear and give you the right advice on how to install it.
  • Matt from Reno

    Posted on 7/14/2020

    When I replaced my stereo, I had four leads from a second harness on the old stereo. No one has been able to tell me what the extra leads are for. They are blk/wht x 2 and brn/wht x2. Am I supposed to have connected those two together when I replaced my unit with an aftermarket unit? We can't get anything working at this point, including the vehicle.

    Commenter image

    Jon Paul from Crutchfield

    on 7/14/2020

    Matt, Sorry to hear that. If you bought your gear from Crutchfield, you can call Tech Support for free help troubleshooting your system. If you purchased your equipment elsewhere, you can still get expert Crutchfield Tech Support - 90 days-worth for only $30. Check out our tech support page for details.
  • maureen lasher from kingston

    Posted on 6/22/2020

    Ihave a 2008 chevy trailblazer Lt. The chimes and radio are barely working. When you turn the radio up it has no base all treble . It came back on normally but when i turned it off ,the vehicle to wash it the chimes and radio did not work right again

    Commenter image

    Jon Paul from Crutchfield

    on 6/22/2020

    Maureen, Hard to say from here. Could be a bad connection, or it could be the sound of an old factory receiver nearing the end of its days. When you enter your vehicle's info into our Outfit My Car tool, you'll see which stereos fit your car, plus the correct harness. If you have any questions, our advisors are available via phone or chat.
  • Thomas Ketcham from Coloma

    Posted on 4/29/2020

    What if you have the Bose deck

    Commenter image

    Jon Paul from Crutchfield

    on 4/30/2020

    Thomas, The radio removal and replacement instructions are the same for both the base and the Bose systems. When you enter your vehicle's info into our Outfit My Car tool, you'll see which stereos fit your SUV, plus the correct harness. If you have any questions, our advisors are available via phone or chat.

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