Heat went out in my '14C2S on the way to the dealer this morning for my 4yr/40k service. I'm 6 weeks out of warranty, so I'm hoping they goodwill the repair, assuming that it's a COV issue. I told them when I dropped it off that there is known issues with the COV failures. So, we'll see.

 

I just bought a 2014 991.1S last month, It is out of warranty, and I have no heat and no defroster - just failed this week. Is there a way to diagnose the valve with an electrical power source and/or voltmeter to identify it as failed

 

Here is a pic of a changeover valve (COV) older version “C” that was in my 2014 991.1S vs. the newer version “F”. I replaced 3 of them last night, and one of them included the failed unit that was preventing my heater/defroster from accessing hot air from the heat exchanger. I replaced the three that were readily accessible without removing the rear bumper cover. It’s nice to have heat and a fog free windshield in the morning. 😊. I will likely replace the others when I need to remove the rear bumper cover in the future.