Fall is quickly approaching and I would like to get this fixed soon. I have a 2005 Jetta 2.5L. The hot/cold knob “seems” to control the heater module, but it takes several weeks for it to engage. Example, when the weather starts turning cold (like now), I can turn knob to hot… nothing. If I leave it there for a couple (or even 4) weeks, the heater will finally kick in, and I mean melt your face hot. Then in the spring when it starts warming up, I turn to cold, and it takes about 2-weeks for it to switch back to cold. So heater in the morning, and A/C in the afternoon is out of the question. Any suggestions