If not for the heated seats, I'd be freezing my butt off here in the great white north.
'07 X5 4.8i N62. No heat coming from either passenger or driver side vents, only cool air. Here's what I've checked / done so far:
- called up faults in ISTA. Unfortunately it seems ISTA cannot communicate with about 1/3 of the modules including JBE and IHKA, so I can't see any fault codes from there
- blower fan is working properly at all speeds, and selecting custom settings directs the air to footwell / face / windshield as expected.
- coolant level is fine, coolant reaches operating temperature of ~100C.
- cabin controls at full hot
- engine fan comes on intermittently as expected
- I reflexively replaced the heater control valve, but that didn't work. Both the new and old valves bench test fine: valves normally open at 0V, and closed at 12V. I disassembled the old valve and the seals were OK so nothing went downstream to clog the heater core.
- I purged the cooling system of air when I changed the heater control valve, so I don't suspect an airlock in the heater core.
Warm coolant just isn't making it to the heater core.
Here's what I'm going to try next:
- although I no longer suspect it has anything to do with the heater control valve, I'll complete my checks: verify that the ground is OK, and that there's 0V at the connector when calling for heat, and there's 12V and a solenoid click when not calling for heat.
- check the auxiliary water pump (how?)
- verify that the heater core isn't plugged (how?)
- see if I can resolve the ISTA module communication issue, but I don't know where to start
Anything else I should check?
11-24-2022, 06:07 AM
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