This is a message to everyone having this problem with the high pitched noise in the cab. My truck has been in the dealership going on 3 times now and no fix. I don't think there is a fix. The sound comes through the radio but that doesn't necessarily mean thats the source of the sound. It could be coming from any of the electronics in the vehicle. On my last visit I was offered a sum of $ to end my pursuit of the problem. I declined. That being said I have commenced with learning all about the Lemon Law. I advise all to do just that. Document all service to your vehicle!

 

Look up the LEMON LAW!!!!!!

 

It's the fan in the radio.

 

I don't think it's the fan. I think it's some kind of voltage induced noise by some component in the radio - but not the fan. The fan would operate at constant speed but in an earlier comment, someone said that if you cover the light sensor on the dash and turn down the brightness display, the noise get's quieter. I tried that and it worked which leads me to believe that the noise is generated by the radio display and not the fan.

The bottom line is that GM is obviously not stepping up to fix this problem. My dealer told me that GM told them not to attempt any repairs because this was a known issue. However, GM has not followed up in six months.

EDIT 3/12/13: Based on my recent interaction directly with GMC, it was likely that my auto dealer never followed up with GMC to actively find a resolution. See my following post.

 

UPDATE

I submitted a request to GMC via their web site regarding the radio noise and they contacted me back within 24 hours via phone. I explained the issue and they contacted my dealer, who then made an appointment for me to come in. After I explained the issue and showed them how to reproduce it, they tried a software update (which did not work) and they ended up replacing the radio the next day. I am happy to say the replacement radio does not have the loud high pitch sound coming from the display. I have tested it over the last 5 days and it seems to be resolved.

 

I have had the Bose system replaced 3 times with new speakers, I have contacted every one possible in the last three years since I bought the truck brand new and got nothing but the run around and constant bull **** from Chevy so I finally fixed the problem. I went and traded it in on a 2012 FORD KING RANCH TODAY guess what the radio sounds great. I have always been a Chevy man until this nightmarish experience. I see how Chevy treats there loyal customers and it sucks. So any of you still getting the run around on the high pitch noise they say is normal tell them to kiss your *** and go Get a FORD they seem to appreciate there customers . STEVE

 

I had the radio replaced and still have the sound. Very frustrating!

 

OK I've been going through this noise thing for approximately 6 months. The truck has been looked at 3 times by my dealer. They replaced the radio and I still have the noise. One of there Engineers looked at the problem last time it was in and this what was said. " A very slight whine/pitch noise that varies with brightness, this is a normal characteristic of the radio. Dealer has performed Bullrtin #PIT5166C with exchange radio. Vehichle conforms to GM specifications at this time. Translation-"Dave you chump-you should have known better than to buy a Chevy. We don't know what causes the problem and through double speak we are saying that we are not going to fix anything". Please don't accept this line of complete bull**** and keep fighting to make them do the right thing. I am now in full pursuit of the Lemon Law. Go to the New York State Attorney Generals website and look up Lemon Law and get going.

 

They replaced my radio also but I still have the noise.