I have a 2000 BMW. I replaced the battery on it about 4 months ago. After doing this the air conditioner will blow hot air for no reason. The air conditioner can be off and the hot air still comes out. The truck has dual climate control where the driver and passenger can be at different temps. What's more, if I turn the truck off and back on the problem corrects itself. Does anyone have any suggestions and what problem could be? If I DIY, do I need the autocom cdp diagnostic tool for it???