2016 Golf sometimes heater cannot be turned off

[Sage]

Seems to happen when the car gets up to operating temperature I get slight but very hot heat from the aircon vents and the only way to stop it is to turn on the cold air conditioning. Anyone seen this?

[Umai Naa!!]

Does it still blow hot air when you've set it to cold and no aircon?

[Sage]

Good question I'll try that. I think it still blows hot though I'll try and post back.

[Splashalot]

My 2017 Trendline did this occasionally. Was a bugger over Summer when it insisted on blowing warm air (without AC on, that is).

I resolved it by trading it on a GTI

[Umai Naa!!]

Without A/C, and set to cold, it'll just blow ambient air around the cabin.

[Splashalot]

Without A/C, and set to cold, it'll just blow ambient air around the cabin.

My Trendline was blowing warmer-than-ambient air in those circumstances. Clearly the heater was still on to some extent, even when set to full cold. Everyone in the family noticed it. Never had this before in any car I've owned.

[Umai Naa!!]

It'd be interesting to see what the blend flap position was at, and what the vent temperature sensors were reading.

Bear in mind these don't have a heater tap on the outside. Just a flap over the heater core under the dash. The more open it is, the more heat is added to the air passing over it in the ducting.

[crainger]

It'd be interesting to see what the blend flap position was at, and what the vent temperature sensors were reading.

Same here. I'm not 100% sure about Golf, but in my Falcon when it was blowing 100% on one side it was a broken mixer shaft on the blend flap.

[Sage]

this hasn't happened again since. If i didn't know better i would think this happens when the car is at higher temps. (Usually in traffic) also Melbourne has been pretty cold of late. Btw i also noticed my aircon does not work very well compared to my 13 year old Golf MkV. Maybe related? Going to troubleshoot more when it starts doing it again.

[Sage]

finally happened again yesterday. pipping hot air gently wafting from vents when all aircon is set to OFF. I turned on the cool air without aircon and it fixed it.. though very strange i think ill take it back to the dealer though difficult as it's intermittent.

[Idle]

Might be flaps not fully closing or tap not shutting off.
My aircon (2013 Golf TDI) was thoroughly inefficient at delivery, many passengers commented on it.
Complained about it at the first two services and was assured all was perfectly normal -- at the third service I forgot to grizzle about it, and they fixed it...
Aircon is now as good as any I've used.

[Sage]

Thanks Idle do you know what they did to fix it? My aircon is also pretty *****.. worst i have seen on any of my cars..

[Splashalot]

Air vent blowing warm air? - GOLFMK7 - VW GTI MKVII Forum / VW Golf R Forum / VW Golf MKVII Forum

One person measured the air temp coming from his vents with AC off and temp set to "Lo": between 6 and 15 degrees above ambient temp! (US forum, so I assume Fahrenheit)

[Sage]

15 degrees Fahrenheit is actually Negative 9c so it was above ambient then i assume he was talking about Celsius!

And yes mine comes out piping hot even when i was driving around with it being 14c outside

[Splashalot]

I assume that US post is interpreted like this:

Say, 70F = 21C. Increased by 6F = 76F, so 24C. Increased by 15F = 85F, so 29C. So on a 21 Celsius day, a range of Celsius 24 to 29 degree air coming out of the vents. That pretty much accords with what I was feeling. (all temp numbers approx.)

Either way, the result is hotter than ambient air is coming out those vents!