Have a 2014 Passat TDI SE Manual with 72k miles on the clock and I do not have heat at all from either side of the cabin (have not checked foot vents). I have heard about the issues with heater cores regarding the lack of heat on the passenger side, but not much about the general lack of heat overall. If anyone with the same experience could just tell me about it, it would be much appreciated as my local dealer will be charging a $120 diagnosing fee. I would rather see if I can figure out if it is a guaranteed heater core issue than bring it in for diagnosing only to find out that it is not. If it is not the heater core, I'll probably not fix it at all and just weather it out as I plan on selling the car back towards the end of the deadline anyways which is coming up next year.