JonFox5

Hi MicMac, sorry for the late reply but appreciate your post. I'm certainly not opposed to troubleshooting the many possibilities and would rather have more things to discount than too few. Thanks for all the pointers, plenty of things to start with and the cabin sensor seems like an easy thing to tackle first (I'm not too bad with a soldering iron). Am I correct in thinking there are two cabin vent temp sensors, one either side above the flap motors?

Our new to us 06 Octavia 2.0 TDI has no heat coming from the blowers. A couple of weeks ago I had the glovebox and trim out from the passenger well and managed to get eyes on the heater matrix/core. Both pipes were too hot to touch so I guess that rules out a blocked matrix and confirms my suspicion after touching them inside the engine bay. I could also see both the bottom and top motors moving depending on the set temp or blower position and plenty of air is coming out (although cold) so presumably blower motor is ok. I also disconnected the temp sensor and that didn't change anything. Also tried the flap repositioning trick. Nothing. Since then I’ve managed to play around and today during some testing I disconnected the passenger temp sensor again (which resulted again in nothing) but then went a step further and disconnected the passenger temp flap motor just below the temp sensor and I can finally get some Luke warm heat to come out the driver vent. Plugged the motor back in and drivers side back to cold so it’s definitely repeatable by unplugging it. Like I said, it’s only luke warm but does help on these cold morning commutes. Does anyone have any suggestions why disconnecting the passenger flap motor might provide some heat to the drivers side? Starting to wonder if the heating matrix / core is actually as hot as it feels (touching the internal pipes off it) and if disconnecting the motor is reducing the air flow over it and so directing more of what little heat there is towards the drivers side? Engine gets up to temp at 90c and stays there, no overheating issues, no scary looking coolant or mayo oil cap or loss of coolant. I've tried every combination of temperature, blower setting, AC on/off, recirculate etc. Just can't get any heat into the cabin even though the matrix is clearly hot. Any other pointers for me please? Can I manually force the hot/cold mix flap somehow as guessing thats the only thing left even though I can see the motor moving it. VCDS isn't showing any errors for HVAC, though I'm happy to monitor some levels if someone can advise what I should be looking for on there?