Heating Issue

[willster174]

Hi guys

I have done a search but couldn't find anything about my specific problem.

I have a 2005 A4 2.5Tdi Cab and am having a weird problem with the climate. It blows out cold air fine and the air con is working no problem but if i want the heating on the it still only blows out cold air.

Maybe i would get some thing slightly warm for a second or two but then it goes back to being cold even on the 'High' setting.

Does anyone have any ideas? Some one suggested it might be the head unit but i cant see how as all else seems to work fine??

Thanks

 

[archemist]

hi. not much help but some thoughts:

1. have you vcds and done a scan?

2. do your flap motors operate ok? can you get / tell the difference when you change outputs manually - screen / footwell etc

3 does car run at the proper temperature (c.90')? Have you or anyone else done anything to the cooling system - airlock in heater?

4. IIRC there's a temp sensor in the CC unit above the centre led - this has a little fan to it. When mine failed (in combination with dodgy flaps) caused it to run hot / cold hot but not quite as you describe

I have a spare 'AA' (the 16 degree one) CC unit available if you're interested - if yours is in good nick (fascia / buttons) you can swap the rears over.

 

[quattrojames]

As mentioned, a VCDS scan would be helpful, it sounds a bit like one of the temperature control flaps is sticking or something. Take the glovebox out and have a look at the control rods and make sure they move as you adjust the air direction, temperature etc.

 

[willster174]

Cheers guys for your replies

I will take a look and investigate further. The car runs at the perfect temp spot on 90 and the flap motors seem to work fine. The only thing which doesnt is a lack of heat.

Thanks Archemist if I cant solve in then might have to go down the CC route. Oh and yeah mine are in great condition no wear at all

Keep you posted

Thanks

 

[archemist]

i'm midway between lincoln and scunny (it keeps filtering out the proper name!) if you need a vcds scan

And

 

[willster174]

Cheers thanks matey

But think i may have found the problem. There seems to be a build up of yellow colour limescale type stuff form the header tank. Am going to have that replaced and the system flushed through and see if that helps.