One problem related to front seat heater/cooler has been reported for the 2006 GMC Sierra. The most recently reported issues are listed below.
The driver's side seat heater randomly comes on. If you turn it off it comes right back on again and cycles through the various heat settings. It creates a dangerous distraction in the florida heat. I've taken it to numerous dealers, none of which can fix it. I call gm and they won't even consider it until I take it back to a dealer saying they will only get involved if I have taken it to a dealer within the last 30 days. One dealer told me that was a lie, there is no 30 day requirement. This issue is more of a distraction than texting. Looking it up online it's a common problem but gm denies it even though gm did issue a TSB to have the drivers door module reprogrammed. I had that done and it made the problem worse. A straight up safety issue. I have the same problem with a 2005 suburban and filed a complaint on that one too. Nothing came of that either so it appears this site and agency is nothing more than a sounding board. Gm and NHTSA cannot afford to distance themselves from this.