Hi

 

I have a 2007 OCtavia 2 1.9TDi, with Manual Air con (not climatronic). It gets up to temperature, but I cannot get hot air from the vents.

 

I have read about issues with the temperature flap motor. When I turn my temperature control to maximum cold, I cold hear the flap motor move. If I set temperature to the middle (12 o'clock)m position on the rotary dial, the motor could be heard, but if I move the control anywhere past the 12 o'clock position, no motor noise is heard.

 

I removed the glovebox (6 screws), disconnected passenger air bag switch (with battery disconnected) and glove box light and cooling tube for glovebox, which allowed access to the flap motor.

 

To remove the flap motor, release one screw (circled), then rotate the motor ant clock-wise slightly, then twist the motor to disengage the motor from the top retaining lug (which is on the opposite side to where the screw is), you can then unhook the motor from the yellow actuating lever.

I opened the cover of the motor and then removed the feedback potentiometer (4.7K ohms). I cleaned it with electroninc cleaning spray, measured the resistance of the potentialmeter, which seemed good at all positions. I did note that there was an area at each end of the rotation which was "short circuit". Usually, these type of rotary potentiometers will have a variable resistance for about 300 degrees of rotation, with a linear change of resistance for the full rotation.

I reassembled the motor and plugged it back in without re-fititng it to the actuating lever..

 

The motor moves, but only really when the control is towards the cold end of the temperature adjustment. Even towards the 12 o'clock position, there is no response from the motor.

 

I have read that the motor position may need to be "learned" by the car, but I don't have diagnostics tools to achieve this. Can it be done any other way?

 

If you look at the actuating lever on the motor, the arm seems to stop short of full travel at one end, and wants to carry on driving at the other end, characterised by a "ticking sound" which is the motor trying to drive when the mechanical arm is at the end of its physical travel.

 

I can source a new potentiometer for £2, but will I still need to use VCDS to teach the system about the new potentiometer?

 

Thanks in advance. 

I think you do not need to re-learn the positions as commands come from HVAC controller.

Hi

 

Thanks for the reply.

 

I have seen that the climatronic versions have a hidden menu, where pressing the "ECON" and "Centre Vent" buttons with the ignition ON will perform a calibration of the flaps.

 

By experiment, I have discovered that pressing the "Re-circulation" and "Heated Rear Window" buttons on a car with Manual A/C will cause the temperature flap to go to the hottest flap position (lever moves fully forwards towards the engine) then it will move to the coldest position (lever moves fully backwards, towards the driver). Then the motor will move to the current setting of the temperature control. 

 

With the engine warm, you can then feel the temperature change from Hot to Cold during the test mode.

.

This test routine doesn't seem to result in a calibration of the end positions, as when the temperature control is set to maximum heat, the flap motor does not reach its end of travel, resulting in slightly warm air, not hot air.

 

So the flap motor is capable (both mechanically and electrically) of moving to each extreme of travel, but it is not where it needs to be.

 

If there is an "on board" calibration for manual A/C, using dashboard button combinations, I cant find it

 

 

Could be the temperature sensor(s) may be reporting the wrong temperature. Is there a sensor immediately after the mixer flap?

If you select screen only or feet only, does the air come out at those position at max temp?

10 hours ago, pikpilot said:

Could be the temperature sensor(s) may be reporting the wrong temperature. Is there a sensor immediately after the mixer flap?

If you select screen only or feet only, does the air come out at those position at max temp?

In the climatic (manual A/C) I think there is only one sensor:

 

 

Which is in the centre of the three buttons which control the system (Heated Rear Window, A/C On & Re-circulate), which monitors cabin temperature, and adjusts the flap position to increase or decrease the flow of hot air, to achieve the setting on the temperature dial, which does have temperatures marked, implying that it is a closed feedback loop.

 

The positions of the flaps to give air to feet, face or windscreen are mechanically moved with either cables or levers. The temperature is the same no matter what position the vents are in.

 

As I posted before, if I perform the "test mode" (press and hold "Re-Circulation" and "Heated Rear Windscreen" for 1 second, the LED's flash and the temperature flap is moved between the extremes of movement (i.e. Hot and Cold) then returns to the position it was before.

 

Here is a video to illustrate this test mode:

 

https://drive.google.com/file/d/1NAGPJ8SdcwCtLkLfSXc2AReTeeWbYMV4/view?usp=sharing

 

With the engine hot, If I enter the Test Mode, I feel the air change from cold to hot then mixed temperature, but I am setting the temperature control to Hot, but the flap doesn't stay in the "Hot" position"

 

I don't know if this is the original motor or a replacement motor by the previous owner. The original motor end points should already be known by the car, but a new motor (or replacement potentiometer in the original motor) will need to have the end point set again.

 

Any Ideas anyone of how to "re-calibrate" the motor position without VCDS?

Here is the VCDS procedure for performing the Basic Setting of the motor if the V68 Flap Motor is replaced in either the Climatic (Manual A/C or Climatronic (Climate Control Automatic system):

 

http://wiki.ross-tech.com/wiki/index.php/VW_Golf_(1K)_Climatic#Basic_Setting

 

One thing I do know, is that the car was stood for some time and the battery was very flat (0.6V DC) but I managed to recover the battery and it starts the car fine now. 

 

I read on a Seat Cupra Forum https://www.seatcupra.net/forums/threads/climate-control-air-con-problem-help-before-the-weather-gets-hot-again.271744/page-2#post-3041470

That the motor position can be lost if the battery goes flat.

 

I am guessing that Techie (Seat Forum) =Tech1e (Skoda Forum) = AKA Ross in Worcester?

 

Thanks for any help anyone can provide.

 

Regards

 

Russell