Hi

I'm hoping someone can give me some advice please?

As the weather has turned colder I've realised that my heater isn't working. The aircon and fan both work normally but I'm just not getting any heat. I don't know whether this is because the heater core isn't getting warm or because the air distribution flaps aren't working properly. The engine temperature is fine so it doesn't look like a wider cooling system problem.

My local garage say I'll probably need a whole new climate control unit and, because this is a dash out job, I'm probably looking at £4-5K including labour. I'm keen to explore the possibility of a cheaper fix, and happy to do some investigations myself if someone could point me in the right direction?

Thanks

Try & trace the heater pipes from the engine bay into the cabin. If they are getting hot in the cabin, then it would appear to be a distribution flap issue.

Hi John, I think your first port of call after the above would be a code reader, then look under HVAC section for any faults, especially with blend motors ETC. It is a complex system when it goes pear shaped so best of luck and let us know how you get on.

A plus one on the above post, to determine the true reason(s) for the failure, and go from there, even if the dash has to be stripped, £4-5000 sounds very high

Thanks for the replies. Is the code reader I need an IIDTool BT?

it may well be stuck flaps. try cycling through the manual buttons for face only, windscreen, feet etc.

This should show if they are stuck or not.

I've had a good read of the workshop manual. I've got the 4 zone climate control which uses a separate heater core and fan etc for the rear. So why would neither the front or rear heating work? I'm guessing I can rule out a faulty heater core or air distribution flaps?

On further reading my current theory is a problem with the fuel burning heater changeover valve. It is designed to isolate the heating system from the engine coolant whilst the fuel burning heater is in operation. If it is stuck in the wrong position that would explain things.

Just to report that my suspicion was correct. It was the changeover valve. Now changed for a new one and heating is restored.

Good spot John!
Those manuals are invaluable when we start self-diagnosing. I’d never had considered the FBH changeover valve! Currently driving: 2012 L322 SE Overfinch 4.4 tdv8

Past rides:
2014 Audi Q7 3.0d (good riddance)
2010 L322 Autobiography 5.0 Supercharged
2011 L320 HSE 3.0 sdv6
2014 Jaguar XF-RS 5.0 supercharged
2007 BMW 535D
2005 Mini Cooper S

https://www.fullfatrr.com/forum/topic59478.html

An excellent result. Good detective work

I’m wondering if that’s the problem with mine, as the symptoms sound extremely similar. Will get the valve changed! 2015 3.0 TDV6 Autobiography in Santorini Black with black-pack
2020 Evoque P300 HSE Dynamic
Past RR’s: 2018 SVR, 2016 Sport Autobiography SDV8 and an SDV6.

Quote:

I’m wondering if that’s the problem with mine, as the symptoms sound extremely similar. Will get the valve changed!

Well found John, glad to hear you sorted it for a reasonable price too

Its also worth knowing that the valve is available as Bosch pt. no 1147412207 (its also used by Mercedes)
Many places show out of stock at the moment but UK-carparts seem to have stock at half the cost of the part from JLR