15 ohms should be ok. The computer will look for a close circuit.
Use DIS and follow the steps in the Mao cooling error or connect a light bulb on the connector instead the heating element and see if the error comes back.
Do you have any symptoms other than the INPA code?

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4.8is 2004 imola red
4.8is 2005 Black on Black - DINAN/2 sold
4.4 2004 X5
2003 330xi
2008 328xi - sold
4.4 2000 X5 - sold