E39 540 - help with air con - drivers side!

[E1DJH]

The aircon sytem, which i run all the time, has suddendly stopped working on the driver's side, and blows very hot air.

The passenger side works just fine.

So, is it possible that a hose has become disconnected or something similar.
If so, can you suggest where i should start looking (can you tell i'm not very good with these things ? )

Many thanks for your help

[E1DJH]

B'stard Child said:

Sounds like a heater valve failure and some helpful stuff

Many thanks for that BC. It seems that this was resolving a "no heat" problem, and mine is a "too much heat, no cool air" problem, this looks like it will be a good place to start.

Anyone else got advice please?

[E1DJH]

SJobson said:

There are temperature sensors behind the little grilles in the centre console, one for each side. I could imagine that if the driver's side stops working but the passenger's works OK, it'd have the effect you describe.

Thanks for that, i'll have a poke around in the morning.
Do you happen to know if these sensors are easy to get to?

[E1DJH]

Well, thanks to the help here i removed the heater control valve assembly chappie, and took it apart.
The two smaller cylinders, mounted vetically, seemd to be in perfect condition. Nice and shiney, with plenty of movement.

When i took the bottom, horizontal cylinder apart, i found a black plastic impeller (BC you refer to this as teh motor unit) which on first sight seemed ok. Then i found three bits of flat plastic floating around, and discovered that these were blades that had snapped off the impeller ( i couldn't find the fourth one).

So, it seems as if this is broken, so i hope it is the extent of the problem.
Does anyone know if i can get a replacement impeller, or do i need a complete unit; and either way, where do i get one from?

The other problem is why did these snap. Something must have got in there! What, how, and how do i know where it is now?

Many thanks again

[E1DJH]

Many thanks BC.

I'll get a new unit, and see what happens from there.

[E1DJH]

New unit purchased from BMW (they called it a water valve) - £150
Fitted last night, which was surprisingly easy really for a non-mechanic such as me.
Short test seemed to indicate problem is gone, so have a 300 mile round trip today to test the little blighter.

[E1DJH]

Hi BC.

I paid list price from BMW. It seemed a bit steep to me, as i only really needed the impellor, but then i considered how much i have saved by you diagnosing the fault rather than them, and for me fitting it. I've just got back from a round trip down to Somerset, and all seems well, which is nice.

I rang the local dealer, Coopers in reading at about 11:00 am yesterday morning. Said they could get it delivered in to them yesterday afternoon, so i went for it.

In recognition of the help you have given, i would be delighted for you to have the old one , although i thought you had got yourself sorted? If you want it, i'm in Berkshire -where are you?

Are you planning to go to the PH Sunday Service next week end?

[E1DJH]

If you PM me your address, i'll be happy to post it over to you.
If you stick the impellor from your old unit into this one, you should have a good spare.

My car, well it is wife's actually, has only done 63k miles, so it seems a little early for this to fail. Looking at the impellor, i can't understand how the damage ocurred, but i'll keep my fingers crossed that it doesn't happen again. If it does, i will recognise the symptoms,and will have the whole system drained to see if anything floats out.

Thanks again for your inyterest and your help.
Cheers, David