2025gmcsierra
New member
Yep. PAC chime setting has no effect. This is not a chime. I have no idea what it is.
New and simple Bose bypass with full Signal Sound
- Thread starter phobby
- Start date
ATXAT4
Member
Curious if you have the 7 or 12 speaker setup? There’s a center channel in the 12 speaker that I am not sure is covered by the GM71.
2025gmcsierra
New member
I have the 7 speaker version. No center speaker.
I've discovered that the tone comes from the front left channel through the pac.
Working on figuring out if the pac is defective or of this is an audio tone arriving via the GM Ethernet stream.
I've discovered that the tone comes from the front left channel through the pac.
Working on figuring out if the pac is defective or of this is an audio tone arriving via the GM Ethernet stream.
CaseySierra2020
Member
I've got the 7. Not sure about the other person.
CaseySierra2020
Member
Yah, it's definitely the front left. How would you go about figuring this out? The fact that not everyone is having this issue, makes me wonder if it's a defective unit.
2025gmcsierra
New member
It could be a harness issue. Something about the connection to the amplifier and car wiring could be signaling the car to send a confirmation tone of some sort on wakeup. I have no way of debugging that other than to maybe try another harness or another vendor. Hopefully I can get those parts tomorrow and try. Or it could just be a defective pac. I upgraded the pac firmware to latest. No change.
CaseySierra2020
Member
PAC audio told me it was a defective unit. My problem is, they won't warranty it. You should be fine, since your in the states. I'll gladly purchase a new harness and try again, if that solves the issue. I updated firmware as well. No luck. I should have left the PAC unit on the floor. Now I have to remove the rear seats.
CaseySierra2020
Member
Yah, that's a good idea. When I get back behind the seat. I'm going to have it relocated, so it's easier to access.
2025gmcsierra
New member
Had it back at the shop. They tried multiple pac's. All the same. This is an issue with something with this configuration of head unit. The Bose amp works well but installing a PAC produces a loud tone on startup. PAC support was useless in troubleshooting. They said PAC was working fine. I'm unsure if the sound is coming from the head unit, nobody has the tools to troubleshoot what the vehicle is sending to the pac. This tone doesn't sound anything like a vehicle sound, but it may be something the car is sending and if so, why? A function of the body control module? OnStar?
If anyone knows anyone at GM who may be able to troubleshoot the GM CAN and audio system, a reference would be greatly appreciated.
My next step is to try a zen nav TV interface for the truck. The shop has one ordered for me. Once that arrives I'll see if another vendor works the same. And if so, maybe their support will be better.
Last resort will be a delay start amplifier circuit. If this tone can't be defeated, since it's only on wakeup, I could build a delay circuit on the amplifier power sense line that powers on the amplifier. I think roughly a 5 second delay between when the dsp sends power on to the amp would be enough time for the tone to play before I turned the amp on, which would effectively mute it. This is my last resort though, I really want the DSP to be able to circumvent.
CaseySierra2020
Member
Have you made any alterations to the truck? I've made several changes, so I wasn't sure if it was something from a previous modification. I have an after market head unit, so I don't believe that's the source of the problem. I think it has something to do with the onstar module or possibly even maybe a door sensor. PAC audio customer service is of no use is absolutely correct. I've heard they have stolen designs from other companies, maybe that's why they can't troubleshoot it...since they didn't actually develop the technology. Have you seen the updated install document? They added a considerable more information. The only other thing I can think of is these harnesses may not be the correct one for our vehicle? See attached
Attachments
2025gmcsierra
New member
I am very familiar with their install document. As far as I can tell, I have all the harnesses connected properly to theirs. I don't have any other mods.
I have a stock head unit. If you have an aftermarket one, why do you need a PAC? I thought that was only needed to pull the audio stream from the GM head unit.
I have a stock head unit. If you have an aftermarket one, why do you need a PAC? I thought that was only needed to pull the audio stream from the GM head unit.
CaseySierra2020
Member
Ok that's good. The original document was not as detailed. After-market doesn't have RCAs to run out of the head unit. I also had a loop back harness made by John at AIS connected to my Audio Control amp (LLJ customs were backordered), prior to purchase of PAC. It was simpler to just unplug the Bose and use the PAC.
CaseySierra2020
Member
I wouldn't be able to turn off the chimes and reduce the turn signal sound. I'd be back to the same issue with chimes and turn signals being amplified via the amp.
I have a possible idea for you. The A11 radio head unit (your dash is just a screen)under the front right of the dash could be sending the sound. It connects to the front speakers, why? Idk… I’ve been through the entire wiring harness diagrams (1400 pages) on these trucks and never found out why the dash and front door speakers connect here.
You could test these out for the sound.
You could test these out for the sound.
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