I have a 2003 Chevy Tahoe. The tow/haul indicator light comes on when we're not towing. In fact, we've only towed a trailer once back in 2009 and it was a small box trailer from U-Haul. Our mechanic stated that it could be from someone hanging on the shifter while driving but we don't do that. I think it might be the shifter because it seems a little loose but aren't sure.