C5 X7 No heat to cabin

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xu10t
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Joined: 28 Jan 2019, 10:20

C5 X7 No heat to cabin

Post by xu10t »

Lhd dual a/c doesn't blow heat at all. Tried methods: ac on, it blows freezing air. Ac off, blows the same as outside. Temp hi, still cold.
Diagbox gives no fault codes but shows passenger side sensor to be 6700c+some french text. Also pollution sensor shows high digits. I removed the glove box and flap gears, but didnt find the sensor. Can someone give me a repair document or some advice on this?

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GiveMeABreak
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Re: C5 X7 No heat to cabin

Post by GiveMeABreak »

What does your outside temperature display read?

If that is ok and there are no fault codes (which would rule out the heater climate control ECU, then I would be looking at the coolant system and the heater matrix.

Post up the French text your are getting too.

xu10t
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Re: C5 X7 No heat to cabin

Post by xu10t »

Outside temp reads way too low. Is that connected to the a/c logic? Im going to do the diagnostic again today or tomorrow.

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GiveMeABreak
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Re: C5 X7 No heat to cabin

Post by GiveMeABreak »

It does - but if it's reading too low, then I would expect the cabin temperature to be hotter not colder - so you'll need some investigation, Check the outside temp with a thermometer and replace it if it is way off.

Has the coolant been changed recently and if so, was it filled and bled properly?
Then I'd look at the outlet coolant outlet housing to make sure that is working correctly.

xu10t
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Re: C5 X7 No heat to cabin

Post by xu10t »

Turned out it was low on coolant lol. Don't know why though.

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GiveMeABreak
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Re: C5 X7 No heat to cabin

Post by GiveMeABreak »

Ok, keep an eye out then for leaks!

I'd look at hoses first of all, the head gasket area, the radiator for any nicks, water pump etc. Next time you come back from a run and the engine is warmed up, let it idle for a while and see if you can see any drips (but watch the fingers in case the fan kicks in unexpectedly....).

xu10t
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Re: C5 X7 No heat to cabin

Post by xu10t »

Didn't see any leaks after a test run. Oil cap had some moisture but i think it was just condensation. When i took off the coolant cap, it felt kind of loose. I think it may have evaporated over time because the previous owner didn't tighten it enough. I hope it was just that.

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GiveMeABreak
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Re: C5 X7 No heat to cabin

Post by GiveMeABreak »

Ok, so hopefully that will be the reason. Bit it could also account for why the heating is not getting through into the left side of the cabin. If it's low on coolant and there is an air lock inside the matrix, then that could be the reason.