Air Conditioning

[calnorth]

Hi Calnorth

I have turned off the a/c and used the fan only - flow is good both sides. Then used recirculation, with a/c off and the flow is alot stronger. I would also say the passenger side is slightly stronger that the drivers side.

This could explain why the difference between the two sides, but how do you fix?

Cheers


Coops

I was trying to detect if one side is blowing warmer than the other. Engine needs to be warmed up so that thermostat releases water into radiator etc. and thermometer used in vents. At a later point you need to dial in some heat and see if vent temps remain close to same.

[Coops123]

Thanks Calnorth

Yes I believe the passenger side was warmer than the drivers, however I have two temperature probes coming tomorrow to check.

If the one side is warmer, what does that indicate?

Thanks again

Coops

[calnorth]

Thanks Calnorth

Yes I believe the passenger side was warmer than the drivers, however I have two temperature probes coming tomorrow to check.

If the one side is warmer, what does that indicate?

Thanks again

Coops

From the diagrams of the Auto Aircon system I have... you can't fix it. The two dash controls (volume controls?) manage each side of the car as regards vent temperature. Both control internal flaps to meter either heat or cold to the vents. That bit I'm not altogether clear on because diagrams don't really drill down enough into electrical/electronic functions. AFTERNOTE: The Air Mix motors can be changed along with some other items from the AirCon System sides rather than removing the whole under dash unit......

Keeping the system in Manual mode with no Aircon could be useful for the behaviour of temperature to be understood. In a correctly operating system the Auto Aircon is blending by blower...external air, car generated heat and generated cold. Switchable to recirc air of course. Blended air is channeled left and/or right in the cabin. Seems simple but too much electrical and electronic dependencies exist. I'll put the schematic up later.

[calnorth]

The mechanical diagram of whats installed in front of the gear stick under the dash is in next post. Not guaranteed to be 100% accurate. It contains two sets of stepper motors and of interest is item 7 - Air mix Door (Driver & Pax). These motors have no positional reference like a Servo Motor System...so they may not be correctly positioned thus allowing an inaccurate hot/cold air mix. I am not sure of that and it appears that periodically the controlling electronics zero those motors...positionally. As below:

[calnorth]

Aircon Unit Mechanical Diag...may not be 100% correct. For instance I'm not sure that UK cars have a PTC heater installed - item 6. Used for when engine is warming up in cold conditions. If motors 7 A or B get stuck/wrongly driven somehow the cabin temp is going to be wrong (hot or cold overall or side to side). What I can't see from this diagram is what channels left and right outputs from heater/aircon matrixes (4,5,6)...other than manual vent blanking. Perhaps there's a dual manifold?

[Coops123]

Calnorth

Fantastic - thanks for the information.

Cheers


Coops

[calnorth]

Additional diagram showing block diagram of electrics/electronics: (Not necessarily 100% correct)