Before I take my dash apart..?

[GT500]

Having not had working demist since I bought my RS2 I have just pulled the codes and wondered if anyone has had similar? 01272 Positioning motor for central flap V70 41-blocked or no volts.
00603 Footwell/defroster flap V85 motor.
01274 Air flow flap motor V71
I guess something must be common to all motors,

Any ideas?

Cheers,

[Fat Audi 80]

Is this a LHD with Climate by any chance?

[S2central.net]

With those codes - yes it will be... I'll hit the books tonight and see what is suggested but by first sound of things it could be most of dash out to access the boogers. COuld be mechanically stuck flap or dodgy actuator... Though seems odd to get multiple faults like that on disparate items. Tried resetting the climate control unit (or just pulling its fuse) to see if that realigns the photon combustor...

[S2central.net]

The schematic is here of course - http://www.s2central.net/S2_Schematics/B/B75.PDF

Lots of sensors share some pins - look at C8 and A9 for example, but why no fault called up on V68 in that case ?
Interestingly the motors have individual pins so it could be a fault inside the head unit, but I wouldn't condemn it yet !!

Maybe bad earth or dicky contact along the way... Worthwhile pulling the head unit and checking all the wires are tight... Though all the motors are wired on the 'D' block....

[S2central.net]

Check fuses 4, 12, 14 and 17.

[Fat Audi 80]

I like to check where I am starting from.

I know NOTHING about the LHD Climate.

I am bowing out now.

[S2central.net]

@GT - just checked the books and there is no mystery here... Almost certainly a dicky contact if the head unit is healthy... No way you have three faulty positioning motors.

You can check across pins 1 & 2 of each of those position motors is in range 20 to 100 ohms... And use the schematic to verify the same readings are obtained at the head unit - connector block D (16 pins).

V85 and V70 can be got at with the footwell ducts removed... But V71 is a booger - need the heater out for that as best I can tell.

[GT500]

Fantastic! I will get to it in the morning,
Report back in then.
Hope it's not a heater out job!!!!
Many thanks for your help!

[johne]

Had a look at mine - which as Paul knows is RHD, so may be different to yours.

There's no way you can get at the temperature flap motor with the unit in the car so that would be dashboard out but you could be lucky with the two other flap motors which work screen/feet and the central air outlet.

But, as Paul says, I doubt two motors have gone at once. As well as measuring the resistance of the motors between pins 1 & 2 as Paul suggests, you can also connect a 9 volt PP3 battery to pins 1 & 2 and you'll hear the motor run. Reverse the connection to drive the motor back the other way. It takes about 15 seconds for the motor to move the flap from one end to the other.

You could also try swoping over the connectors to the flap motors - the pinout of the 5 pins for the 3 motors is the same. That way you could find out if the drive from the ECU is faulty or it's the motor depending on if the flap works when you change over the lead driving it.

There are 4 connectors on the back of the climate ECU. Connector "D" which is the smallest one but the one with the large size pins drives all the motors. Try unpugging the connectors and reseating them - you never know, you could get lucky!

One thing that is common to all motors is the reference voltage feed to pin 3 on all the motors which comes from the ECU pin C8. Should be about 5 volts. Without this the ECU won't get a voltage back from the motor pin 5 which tells it the position of any particular flap.

John

[GT500]

Thanks for the help, John,Paul.
So far, no fuses blown, unplugged all connectors on the back of the control unit, refitted and no better.
I have 5 volts at pin C8. Connected 9v battery to pins 1&2 on the rhd side motor and it moves perfectly both ways, never moves no matter where you direct the air on the controller.
I have a B5 A4 in this aft, I will borrow its controller and report back!

[S2central.net]

Good tipoff on the 9V battery there from Johne - great stuff like that is never in the firkin Audi manuals !

@GT - did you buzz out the connections from the D block connector to those motors ?
If they check out in spec (proves connectivity from head unit), then it does sound like a faulty head unit. Lucky you have a spare one - they can be expensive, but you probably need to recode one from a B5 to the weird S2/RS2 application for it to be happy - this is essentially cos we have no compressor speed signal and the B5 unit will complain... I'll dig out coding info for you - but its on here somewhere in a previous post of mine - I have no time to search right now.

Paul

[GT500]

Just tried it, and yes it dosent like the ac part, no flake.
Works the rest, but same problem, no screen or footwell action.

we continue....

[johne]

@GT been thinking a bit more about this. Despite what the codes say, as far as I can tell from what you've said only the screen/footwell flap isn't been driven by the ECU??

That means you do have temperature control? Can you vary the flow from the central vent? If yes to both then only the screen/footwell flap motor is suspect. I suggest going back to the screen/footwell motor and checking 2 things.

Does the motor connector pin 4 go to earth/chassis? It should but it's a tortuous route in the loom so worth checking

Disconnect the motor from the ECU and using the 9v battery again to drive pins 1 & 2, have a look at how the resistance varies between pins 3 & 5 and 4 & 5. The resistance between 3 & 4 should be constant - 5K from memory but may be wrong. The actual value doesn't matter but say it's 5k for this example. As you move the motor one way the resistance between 4 & 5 will rise from zero to 5k as the motor travels from one end to the other. At the same time, the resistance between 3 & 5 will go down from 5k to zero.

Finally, when you've finished, drive the motor to the other end from where you found it and reconnect the ECU. Once reconnected to the ECU, does the motor drive to a set position and then stop or does it just stay still?

If it doesn't move, that suggests to me the ECU isn't getting any position information from the motor so if the wiring isn't broken it's looking like a new motor is needed.

If it does move and then stop, the motor is working under the command of the ECU. As we know the ECU isn't faulty that means some external sensor is telling the ECU something that makes it drive the motor to that position. At that point my brain aches and I need to think a bit more about it!

[GT500]

Update:
Did some more testing this aft and sussed the blue motor is doing sweet fa.
Just been on to TPS and they are £69 to me ! ordered it ANNNND its on back order!
Should get to know on monday a possible date.

wonder if and A4 one is similar?

[johne]

I believe the motor certainly could be the same because I converted my RHD S2 to climate control using the central unit out of a RHD A4 that had climate control but I don't have access to parts number lists to prove it - Paul N may be able to help there.

John