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Question, have you looked from both sides of the center console? While looking thru these schematics I found the diagram for the "Radio Speaker Amplifier" and it's in the exact same place diagram-wise as the ANC. Is there a chance that it's on the driver's side and you just can't see it?
Does this site possibly have schematics for blazers without factory amps? Or maybe in a different location?
 

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Discussion Starter · #22 ·
Does this site possibly have schematics for blazers without factory amps? Or maybe in a different location?
I've done some more digging. I looked on my car, drivers door sill, look down in the rocker panel and found the silver GM sticker with the qr code. Apparently that QR code gives you all the codes for RPO (Regular Production Options). So I pulled my code, got all the little codes. In that I found out my car has IOR. That is my infotainment configuration. So then I pulled the description of the IOR system and I found "Active Noise Cancellation (if equipped)". So then i went and looked at the IOS/IOT models. There is no listing of active noise cancellation. However there is a section that says "Audio Amplifier (if equipped)". So i'm wondering if since these are all listed as "if equipped" that it's optional and in order to allow buyers to outfit their models they ship them with the microphone grills installed in the headliner but there isn't actually any microphones or module installed? It's one theory so not sure.

Edit: just pulled up lljcustoms site to see something and the ANC Bypass also says "select vehicles". So this has to be it, ANC is optional, if the module isn't there in the center console looks like you don't have it/don't have to worry about it. From the schematics straight up and down heat sink lines on module is ANC, diagonal is amplifier.
 

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Discussion Starter · #23 ·
Does this site possibly have schematics for blazers without factory amps? Or maybe in a different location?
More info from the description page:

Audio Amplifier (If equipped)

Amplifier Interface
A fused battery voltage circuit provides the main amplifier power. The audio amplifier (when equipped) is a participant on the Ethernet bus. The audio amplifier receives audio signals and control information from the Radio. The Amplifier receives battery power and ground from the vehicle harness, and also communicates on GMLAN.

Amplifier Operation
The purpose of the amplifier is to increase the power of a voltage or current signal. The output signal of an amplifier may consist of the same frequencies as the input signal or it may consist of only a portion of the frequencies as in the case of a subwoofer or midrange speaker. The audio amplifier amplifies the signal and sends it to the appropriate speakers.
Each of the audio output channel circuits (+) and (−), at the audio amplifier have a DC bias voltage that is approximately one half of the battery voltage. When using a DMM, each of the audio output channel circuits will measure approximately 6.5V DC. The audio being played on the system is produced by a varying AC voltage that is centered around the DC bias voltage on the same circuit. The AC voltage is what causes the speaker cone to move and produce sound. Both the DC bias voltage and the AC voltage signals are needed for the audio system to properly produce sound.

The audio amplifier is also responsible for operation of active noise cancellation if equipped. Refer to Active Noise Cancellation Description and Operation for more information.


So yeah, there will either be one or the other there in the center console. If nothing there, it's not equipped.
 

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I've done some more digging. I looked on my car, drivers door sill, look down in the rocker panel and found the silver GM sticker with the qr code. Apparently that QR code gives you all the codes for RPO (Regular Production Options). So I pulled my code, got all the little codes. In that I found out my car has IOR. That is my infotainment configuration. So then I pulled the description of the IOR system and I found "Active Noise Cancellation (if equipped)". So then i went and looked at the IOS/IOT models. There is no listing of active noise cancellation. However there is a section that says "Audio Amplifier (if equipped)". So i'm wondering if since these are all listed as "if equipped" that it's optional and in order to allow buyers to outfit their models they ship them with the microphone grills installed in the headliner but there isn't actually any microphones or module installed? It's one theory so not sure.

Edit: just pulled up lljcustoms site to see something and the ANC Bypass also says "select vehicles". So this has to be it, ANC is optional, if the module isn't there in the center console looks like you don't have it/don't have to worry about it. From the schematics straight up and down heat sink lines on module is ANC, diagonal is amplifier.
Okay since I don't gave either I should be good
 

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Discussion Starter · #26 ·
Okay since I don't gave either I should be good
Just to follow up. I had time to pull apart my center console yesterday and turns out I don’t have the ANC box. The picture just made it look like one was there 🤦‍♂️. So I just did the front passenger side headliner mic delete. It was super easy. Disconnect battery, Unscrew handle in the headliner, remove plastic cover over seatbelt pillar, pull headline down just enough to reach in and disconnect the wire going to the mic. Putting it all back together just requires a thin flat head to make sure the rubber trim on the edges are back over the headliner. After all that I went and re-did my input sens on my amp. I was actually running it too low. Drove around town to test. No errors from mic being unplugged, sub sounds good and loud, no feedback.
 

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I just installed a system in my wife’s 2020 Blazer that does not have have the Bose system. I did not use a T harness, I stripped alittle of the wire coating and soldered 2 female rca ends behind the connector on the radio box under the dash by the right kick panel. If anyone needs wire colors I can post the diagram I found. I have not disabled ANC and it is a problem. I would assume it’s on the box that the speakers plug into. I’d rather not go thru the headliner. Any of y’all that bought a T Harness show what plug or wire affects the ANC or how to disable it?
 

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Discussion Starter · #28 ·
I just installed a system in my wife’s 2020 Blazer that does not have have the Bose system. I did not use a T harness, I stripped alittle of the wire coating and soldered 2 female rca ends behind the connector on the radio box under the dash by the right kick panel. If anyone needs wire colors I can post the diagram I found. I have not disabled ANC and it is a problem. I would assume it’s on the box that the speakers plug into. I’d rather not go thru the headliner. Any of y’all that bought a T Harness show what plug or wire affects the ANC or how to disable it?
Depends on if your car has an anc box. If you don’t have a little silver box in the center console I’m not sure where the box is or if the car even has a box. It might have it built into the radio. For my situation I thought I had an anc box but when I pulled apart my center console there was nothing there. See my reply right above yours. Single mic delete on the front passenger side is the way to go. It’s so easy. One screw on headliner handle. One screw on b pillar. Pop b pillar clip pull down headliner the slightest bit to unplug the mic. That’s it. Unplugging just one mic was enough to disable my anc.
 

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Depends on if your car has an anc box. If you don’t have a little silver box in the center console I’m not sure where the box is or if the car even has a box. It might have it built into the radio. For my situation I thought I had an anc box but when I pulled apart my center console there was nothing there. See my reply right above yours. Single mic delete on the front passenger side is the way to go. It’s so easy. One screw on headliner handle. One screw on b pillar. Pop b pillar clip pull down headliner the slightest bit to unplug the mic. That’s it. Unplugging just one mic was enough to disable my anc.
Yea that’s probably what I’m gonna do and be done with it. Mine didn’t have the silver box in the center console.
 
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