My FJ is a 2012, 6 speed manual transmission with approximately 55,000 miles. I live in the balmy Sonoran Desert of Arizona, aka, "The Valley of the Sun".
A few years ago, I traveled to north central AZ at an altitude of about 6.000 feet. It was winter with temps during the day of 50 degrees-ish and night time temps around 25 degrees-ish. One morning, I buckled up for a drive. After inserting the male end of the seat belt, all seemed well until I drove a couple of miles. At this time, the seat belt warning system began it's annoying beep, beep, beep. While driving, I unfastened the belt and reattached it which did not change anything.
This anomaly does not occur in the Valley. Maybe it's the 110 degree days. Last week, I was in Colorado where I negotiated a pass of 12,640 feet and camped at about 8.000 feet for a few days. The system worked ok.
Suggestions / advice?