Hello. I have heat issues on my 2009/11 bmw 530d with auxilary heating.
Webasto working good, but not heating interior.
I changed all three thermostats to oem. Main was good, transmision was good too just egr one was open. So the result is that now i have ~86C° when driving at 80km/h before was droping to 79C°. At speed 110km/h engine temp. Normal 89-91C°.
If i activate webasto at morning about -10C° outside. Webasto working but blowing cold air from vents. I try to grab hose that goes from vebasto to heater valves ant its very hot. Changed heater valves. No result at all.

 

Heater core might be clogged, or the water valve may not be functioning.

 

Can IHKA control unit be bad and dont let coolant to flow from heater valves?

 

Easiest way to check is to use a voltmeter. Then could be the valve, or a clogged line. If you feel past the valve and the hose is hot, the valve is most likely working. Then there may be a clog somewhere in the hose or the core itself.

 

From webasto coolant hose is going to heater valves, and its very hot, i checked with ISTA live data, webasto very fast heat coolant to 83°C . Thats why i cant hold that hose for long time. But hoses that goes from heater valves to heater core are cold.
I Dont think that heater core is clogged, because when i was changing coolant i applied pressure air to hoses it goes easily without any restriction.
Its like heater valves cuts hot coolant that comes from webasto, thats why i changed them to new ones.
Yesterday readings from ISTA : engine coolant temp. 50°C, Webasto coolant temp. 83°C , IHKA live data "heat exchanger for heating system temperature, right 5°C ",
"heat exchanger for heating system temperature, left 5°C " . On IHKA and CIC temp is set to hotest.

 

If you measure zero and then battery + at the valve connector, then you have a faulty valve.

 

Just measured old valve's on a bench. Circuit is ok. Both valves 15ohm at 23°c room temp.

 

Measure the voltage at the connector; with ignition in run position, set climate to full hot should read zero and full cold should read battery +.

 

7.4v always. Doesnt matter what i set on IHKA

 

Well, that's not good. IHKA CU may be faulty or loaded down (shorted).