My A/C did the same thing on my SO. Wouldn't kick on until operating temps were up. But it seemed only to happen when it was 100+ outside. Never even thought about it being the TST. I took my truck in for the TSB and now there's no issue what so ever. My new problem is the dual climate control. Driver side is freezing and the passenger side is just cool. That's even with both sides on the coldest settings. Any thougths?