AC doing some funny things?

[aztitan4x4]

I have been experiencing something very odd. When I am backing up to hook up a trailer or backing into a parking space or even just negotiating my truck at parking lot speeds that my A/C will start to warm up, but as soon as I stop and put it in park it will cool back down. My truck has been doing this since day 1. It's as if the computer is sensing too much load on the motor from the steering pump and brake booster at the same time that it kicks off the compressor. When I am sitting at a light it runs just fine, even idiling for long periods of time it will never warm up.It only does this at very slow speeds? Has anyone else experienced this so that I can verify if there is something wrong or just normal. THX..
PS it doesn't matter how long I have been driving my truck(ac cooled all the way down)