hi guys. so my 2010 superb estate issue has everyone confused.

the air con blows warm when stood still and v cold when driving. checked gas all ok. replaced high pressure switch no different, replaced aircon compressor switch the one held in with the snapring. had diagnostics, 

so the issue is the fans wont come on when idling yet work when doing dpf regen?.. my man unplugged the aircon compressor,then plugged his unit and and found the air con compressor works fine. checked input to it and was 1.2nm?. we then wriggled wire behind the o/s headlight and the fans came on slow and the aircon blew cold, right so wire issue. took the o/s headlight out stripped all the wiring from the turret to the front  and belled all the wire and nothing found. had another  mate who has vagcom come round. 2 codes 323 vehicle inclination sensor and 1135 interior motoring sensor faulty. we dropped the interior light roof panel thinking that would be were it was to find nothing behind the slots?. he thinks its either ecu not telling the compressor fans to come on or the binnicale. but we have checked the switch current on that and its working?.on the vdcs the fans are getting no voltage with the aircon on?. any ideas please.

also  there is no voltage going to the aircon compressor?.so i presme thats why the fans dont work.

 

when driving along its v cold just warms up when i stop. not good as i want to go to portugal with it

@rockabilly - Well, on the costs nothing except your time argument, I'd suggest starting with 10 minutes of flapperobics. If that doesn't work, I'd check Yell for an automotive air conditioning specialist in a location that suits you.

flapperobics?

 

 

had one ac guys already look at it hes stumped

 

and a very experienced vcds guy. we know the ac compressor is getting no signal feed. what we dont know is why

 

all the vents blow evenly and where they should, hot temp is fine and can be regulated fine.its just not cold on idle in hot weather

 

seen few people have the same issue too but never a resolve. the n280 valve on the compressor has been changed as has the high pressure switch. its showing 50psi on idle running  on the low side but this is because the ac is not running

Edited 13 March, 20197 yr by rockabilly

9 minutes ago, rockabilly said:

and a very experienced vcds guy. we know the ac compressor is getting no signal feed. what we dont know is why

 

This contradicts what you said in the opening post about the air con blowing very cold? If its blowing cold the compressor must be getting a signal

it did when the guy unplugge the n280 valve. he had a unit that connected to the battery and powered the compressor. then the fans came on and cold air blew,

 

its a test unit he has

Edited 13 March, 20197 yr by rockabilly

So wiring break between Climatronic control unit and N280? I can look up pin numbers at the control unit if helpful, in an hour or so.

thank you. but if thats what it maybe i think its beyond me. i presume you mean the binnicle in the car and the n280 valve..if so wow. 

 

may just chop the car in if its that. that i suspect will be a minefield lol

 

can i meter the n280 valve plug?., if so how many wires and what should they read?.

 

not sure where the control unit is? the dash panel/binnacle

 

if anywere i suspect near the compressor where the wire gets most heat

Edited 13 March, 20197 yr by rockabilly
added info

Heat and vibration, yes.

Got a few chores to do yet before I can look at wiring info.

There are two wires that go to N280, pin 1 at the connector is a brown/black wire which goes to pin 4 of a 4-way connector in the 'front left of engine compartment' where it changes to a green/black slightly thinner wire which then goes all the way through into the cabin, to pin 18 of a black 20-way connector at the climatronic unit.  So first test to do on that one is to find this 4-way connector in the engine bay (UK nearside) and see if there's continuity from the N280 plug that far.

 

The wire from pin 2 of the N280 connector is green black, and if that wire is intact, you should see continuity from it to chassis ground/earth. It also goes to the same 4-way connection, this time to pin 3, where it comes out as a brown wire on its way to earth connection somewhere within the main wiring loom.

 

The climatronic unit is the one in the middle of the dashboard where you set the temperatures etc.  Dunno how easy it is to get to the back of it.

thats great thank you.

will be mon when i get to it now as i work away for 4 days at a time and am back in tommorrow..

right guys. so now we are truly bemused. pulled the plug off the compressor. belled the earth all good. checked power. nothing with ign off then ign on a/c switched on motor off 4.3v.then fired the up and 13v?. so it seems to be getting power put not running the fans.

just to add. just removed the climate unit found pin 18 wiring. when the aircon button is pressed 5.3 v  constant to the a/c  n280 valve. does anyone know if this is right

Could be OK. That voltage will vary depending on how much compressor action the control unit is trying to achieve. 

It's actually a stream of 12V on-off pulses, but fast enough that your meter will just show an average value depending on the width of the pulses.  As the pulses get wider, your meter will read higher, and the N280 valve will open more.

 

The fact that you have voltage at the compressor plug means the wiring is intact, especially if you measured between the two pins (which would then test the earth too.)

i suppose next stage is compressor,though that seemed to work ok when he powered it.

 

no vcds code at all.

 

just no compressor energizing

Have a look through this post and see if there's anything you haven't tried yet: https://forums.ross-tech.com/showthread.php?633-Tis%92-the-HVAC-Season

ok

do these models have a fan control module guys?.

 

wonder because it goes cold when you drive if the compressor is on but not the fans?.

 

i ask because they used to come on for dpf regen but not heard them in a while

 

Edited 19 March, 20197 yr by rockabilly

found this on the sanden compressor. mine shows 5.3v out of the control binnacle to the comnpressor. but i suspect i need an asciloscope to really check

 

 

 

7.2 Clutch Inspection

7.2.1 Voltage Check

1. Confirm that the clutch is receiving at a minimum 11.5 V or 23 V for 12 V and 24 V systems respectively. If voltage is not being received at the clutch run a diagnostic on the vehicle electrical system. (Note: perform test with power applied to coil to fully load the circuit)

2. Pulley or Rotor Spin Check 3. With clutch disengage the pulley should spin freely with no wobbling or roughness/vibration

Edited 19 March, 20197 yr by rockabilly

No clutch on your compressor. It's a variable displacement design, controlled by N280 valve.

right so no clutch. so if the n280 is only getting 5.3v from the dash control binnacle do we think this could be the issue. does the compressor turn the fans on or vice versa? thanks for the help so far by the way

 

when running the pipes are not getting cold either. 

Edited 19 March, 20197 yr by rockabilly

VCDS will give you all the info you need, I have recently been chasing a similar fault for several months, in the end it was something inside the compressor, when replaced it worked, had I had access to the test module you had I would have saved a lot of time.

 

VCDS will show a relevant compressor shut down code if it is not being energised, the voltage you have would indicate that it is being energised but it might be parasitic, VCDS will also show what percentage the Climatronic is loading the compressor if it were working.

cheers.j.r tommorrow im down at a friends garage.he hasnt vcds but solaris.hoping to dig deeper

 

yes when he powered the compressor the fans came on slow and all worked fine

 

when another friend plugged vcds in no fault codes were shown?.

Edited 19 March, 20197 yr by rockabilly

The rad fans get turned on by the A/C control unit sending signals to the fan control unit - possibly via the engine ECU  - when the refrigerant pressure rises beyond certain thresholds. 

I think the fan control unit on your car may be integrated with or attached to the main radiator fan.

 

Refrigerant pressure is measured by the G65 pressure sensor in the metal refrigerant pipework. On the cars I know, the pressure has to get to about 9 bar before the rad fans are triggered, and then if it gets to 16 bar, they come on at a faster speed.  I think your fans may be variable speed rather than two fixed speeds, but I don't know enough about the system on recent cars to know for sure.

 

If the refrigerant pressure isn't rising because the compressor isn't compressing, the fans won't come on.

 

As said by JR, VCDS may help establish why the compressor is not compressing.

 

Can you confirm that when you measured voltage at the N280 connector, you were measuring between the two pins of the connector?

Edited 19 March, 20197 yr by Wino