[Solved] Audi a4b5 1.9tdi afn: Understanding Heating Conditions for 1, 2, 3 Candles at -6°C

You mean the water heater? There are two relays controlled from the ECU in the configuration 1-1 low power 1-2 high power, i.e. one relay activates 1 candle, the second relay 2 candles. The controller turns them on based on the alternator load, i.e. the DF signal from the alternator. I know that 3 heat up to 25 ° C of fluid and then 2 to 70 ° C

So, since the high-power circuit works, there is something wrong with a small one, or the alternator is too loaded to check the relay, check the errors in the ECU and do tests because the test is to turn on these relays, I know that in some group in decimal form there is a description of the conditions for switching on these candles