Well it seems like the climate control unit is the trigger for your problem. I am not sure where the ECU or BCM are located on the VX, but if it is under the climate control unit, maybe your heater core is leaking on to it? I had that exact thing happen on an old Maxima. Heater core leaked right on to the ECU. I replaced the core and used a blow dryer to dry out the ECU, worked like a charm. Either eay, it's definitely an electrical malfunction, so either an electrical component is on it's way out and is shorting, or you have a bad/loose wire or connector somewhere. I'd start by taking out the stereo and climate control unit just to get a look at what is going on back there.. Sorry I'm not a lot of help.. this is totally weird.