HVAC issue

sparksuk · #1 1st November 2015, 09:13 PM

Hello guys. I did a scan today because the heating does not work properly and i don't really know from where to start to look for the fault. I have attached a photo. Any ideea ?

Thanks

mannyo · #2 3rd November 2015, 06:54 AM

The control module is the part with the dials and buttons, maybe worth removing and checking the connections are all good.

I have a HVAC fault on mine, but the error in my case relates to the blower controller under the bonnet, and the fault mentions this.

Mechcanico Lee · #3 3rd November 2015, 08:34 AM

Not sure about that code Spark , clear it down do the full systems test with the vcds see if anything comes up , i think first place i would be looking is the water control valve to the side of the pollen filter housing , with engine running feel the pipes going from the engine to the valve , see if the pipes are hot past the valve toward the heater matix , could be the valve stuck closed or could be blocked matrix radiator , are both drivers and pasenger sides not getting warm or is one better than the other .

May seem like a daft question .......the water level is ok ??

sparksuk · #4 5th November 2015, 04:14 PM

The problem is : if the heating is over 23 celsius, no heating goes in the back on the pillars and on the one in the middle back. Only goes on the blower under the front seats. Also on the windscreen, the driver side is still cold air but on the passenger side is warm. Strange.
The water level is ok. Where exactly is placed those valves ? Underneath dash on the passenger side ? Is a box with a filter there ( cabin or polen filter ). Is it easy acces, can i remove that and check it properly ?

Thsnks

mannyo · #5 5th November 2015, 06:02 PM

The valves are under the scuttle panel in the engine bay, the pollen filter is also there.

Open bonnet,
remove rubber trim that runs across the engine bay near the screen.
Lift out both halves of the plastic scuttle covers.
The Pollen filter is under the cover in the centre
The valves are located on the UK passenger side of that centre box, you'll see them with the cover removed.

The rear footwell vents are electrically heated due to the distance from the heater box.

The valves look like the link.
http://www.wolfautoparts.com/4e09596...bly-63759.html

sparksuk · #6 5th November 2015, 09:35 PM

Thank you

in this case it look like an mechanical problem ? Thing is, the cold air (ac ) goes in the back but not the hot air. Or it may be an issue with that valves. I belive is bit difficult to take the whole thing out of there and check them. well, if i know for sure thats the problem i will just replace it. the most anoying thing is when i have to defrost or demist the windscreen, one side ( driver ) blows cold air and the other side is warm.
Also i manage to activate with Vag the additional aux heating !! thanks to this forum, i found all the informations how to do it

)

Mechcanico Lee · #7 7th November 2015, 11:43 AM

Rather than just replacing the valve , take it apart take the shuttle valves out so that the ports are open , refit it all , run vehicle without cap on to bleed air out then see if you get hot air then on both sides .
Take the car for a run as it's hard to get diesels up to temp , if the car gets up to temp and stays constant sort of proves that the water pump impeller is circulating the water ok , I have seen plastic pump impellers spinning on the shaft on some cars , it affects the heating in the car but normally the car will start to over heat somewhat under load