Quote:
Originally Posted by Eddles
Despite setting the rear left fan to maximum and directing it to the footwell, no air would come out of the vent. The same setting for the rear right worked perfectly, and warm air came out of the foot vent. So, I suspected the rear left footwell ducting was flooded with water and decided to use a borescope to double-check at some other time.
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The air flow for the rear floor vents, in the 4-zone temperature HVAC system, are controlled by stratification flaps on the air box under the front dashboard.
As you noted, the floor vent has both a heating element and a temperature sensor.
The ideal path forward would be to run ISTA to look at what codes have been set on the HVAC system (IHKA = A95 or the FKA = A39, the FKA is a slave to the master IHKA ECU).
When using the rear floor vent, the temp sensor is used to regulate the rear floor stratification (air flow).
What you could do, is lift your front seat as high as possible, peel back the carpet on the right side of the vent, and disconnect the connector to the temp sensor. The other connector is for the heating element.
Make sure there there is no water inside the temp sensor connector, and if so, remove, and reconnect the temp sensor.
Test the system again.
BTW, the vent is held in by a 10mm plastic nut, then the assembly slides out from underneath the carpet. I think the only way to get to the nut is to remove the front seat, and in order to peel back the front carpet section, the bass speaker cover will need to be removed.