1999 GMC Sonoma Owner's Manual - Page 23
1999 GMC Sonoma Manual
Page 23 highlights
yellowblue Q: What's wrong with this? CAUTION: You can be seriously injured if you wear the shoulder belt under your arm. In a crash, your body would move too far forward, which would increase the chance of head and neck injury. Also, the belt would apply too much force to the ribs, which aren't as strong as shoulder bones. You could also severely injure internal organs like your liver or spleen. A: The shoulder belt is worn under the arm. It should be worn over the shoulder at all times. 1-17