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Air Cond Blowing cold on right, hot on left


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Hello again.

My air cond has gone mad. It is only blowing cold air (regardless of the temp setting) on the right side of the front (driver's side here). As a consequence it blows really hot air through the left in an attempt to get the cabin temp correct, which annoys my wife no end!

Curiously this all started about the time I changed the cabin air filter (it was totally blocked solid).

I'm getting heaps of errors from durametric. If I clear the error codes a few remain but they all generally come back after a day or two.

The rear air cond is working fine (depsite the errors that seem to suggest otherwise).

Also note my Kessy is stuffed (see my other post) but it's been stuffed since before this all started happening. (I assume this is the error 1336?).

I assume there's a hot/cold left/right servo that's gone and this is causing on-flowing problems. Also I'm note sure what the Gateway error is (1299). There are no error codes on the gateway when I scan it. Can anyone assist with a diagnostic procedure?

The durametric transcript is below. Vehicle is a 2003 turbo with rear air cond option (obviously!).

Thanks!

DS

Air Conditioning Module Identification Part Number 11Diagnoss Number Current Fault Codes 711Servo motor for footwell flap left 713 Servo motor for central vents left 1810 Drive motor for temperature valve right 1596 Servo motor for fresh-air/air circulation flap 712 Servo motor for footwell flap right 710 Servo motor for defrost flap 1336 CAN comfort OFF No signal/communication

1299 Gateway Please read out fault memory

2599 Temperature flap servo motor rear left 2597 Rear left air vent on tunnel

362 Servo motor for volume air flow flap rear left 2600 Temperature flap servo motor rear right 363 Servo motor for volume air flow flap rear right After clearing the faults the following remain... 711 Servo motor for footwell flap left 1810 Drive motor for temperature valve right 1596 Servo motor for fresh-air/air circulation flap 2599 Temperature flap servo motor rear left 362 Servo motor for volume air flow flap rear left 363 Servo motor for volume air flow flap rear right

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Your can bus circuit is playing up.

Could be caused by a faulty control module connected to it or the bus itself being shorted or open circuit.

I would try electrically isolating the front and rear air con modules separately, and see if that makes any difference.

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Thanks

Could you elaborate on how I might do that (isolate each module).

Can I just pull a fuse? or do you mean pull out the control panel (with the temp displays) and disconnect them one at a time?

Thanks

DS

UPDATE

I reset the gateway by pulling the fuse, waiting 10 s and putting it back in, and was able to communicate with it via durametric.

It is not showing any errors at all.

The air cond module is still showing multiple flap servo errors (same as in the second section of my post) but is no longer showing the 1336 and 1299 errors.

I also checked the voltage across my battery (at the jump terminals in the engine bay). With the car turned off it's showing 12.47V, so that seems ok. The battery is about 3-4 years old but when I replaced it last time I put in a really expensive Varta AGM battery, which should last a bit longer than a lead acid job.

Thanks

DS

Edited by darrinsmith
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Part of the KESSY module powers up the Terminal relay which powers up part of the CANBUS system, if the CANBUS isn't operating correctly is can cause issues with convience systems. Can you operate the climate control servo motors via the Durametric and do the go through their full control range?

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I did try using the testing function of durametric, but I was unclear as to what the various numbers displayed meant.

I asked durametric, and they said they couldn't tell me? and that I should refer to the Porsche procedure?

I understand what you mean though, so I'll have another go at it.

I have the service manual, but group 8 (HVAC) doesn't seem to cover troubleshooting, only removal and replacement.

I'll work through the various servo's and see if I can fault them.

I'm sure having the Kessy out of action is not helping....

Thanks again

DS

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Hi

I ran through the "output test" feature of durametric for the A/C module.

I figured out what the 4 display fields are.

1 (top) is the upper limit of the servo/device. 2 is the actual current value. 3 is the value the software is sending and 4 (the bottom) is the lower value possible for that servo/unit.

I can see that for the faulty servo's the software is trying to send various values to the unit, however the unit is "stuck" on a particular value, generally around 70, which is almost half way through the range.

So this now begs the question, is it normal for so many servo's to fail (there appears to be about 6), or is there a fault in the a/c controller (it appears to be working and is happy to communicate with the software and execute functions where it can.

The only thing I want to fix first is my Kessy (see my other post). It's going to be a job to remove it, and next weekend I'm going on anout a 700km round trip (bit of beach driving too!), so I'm going to wait till I get back to fix that. That will at least rule that causing a problem, but my CAN bus (gateway) is not showing any errors, and communicates just fine with the software.

If I get stuck where I'm going I be 350km from anyone who can help.

Happy for any oppinions on the multiple servo failures....

Thanks

DS

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Would you believe I got into the car this morning, and it all seems to be working correctly now?!?!?

The only thing I did differently was I used the "clear errors in all modules" function of Durametric (just under the short test all modules menu item).

However I still suspect the A/C control unit. My car is a 2003 and the unit is original.

Is the control unit the same as the unit with the switches and temp displays on it, just above the ashtray?

That's a relief that thing just pops right out....

Thanks

DS

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  • 2 years later...

Ok finally fixed my Kessy and now I can communicate with the A/C unit again.

I'm getting the same errors still.

I'd like to try getting at the regulator motors so I can test them and possibly replace them.

I have a RHD car, and the regulators are on the LHS of the centre tunnel.

But you can't really get to them as the condenser assembly is in the way.

Can anyone shed any light on how to get to the servo motors in a RHD vehicle.

All the instructions I've seen refer to the LHD vehicles, where the blower/condenser assembly is the mirror image.

 

Thanks

DS

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  • 4 weeks later...

Ok I finally fixed the stupid air cond servo motors. I ordered 3 (defroster flap, left hand outboard, and right hand temperature mixer flap) - My car is a RHD ($280 each OUCH).

I didn't bother with the footwell servos as it never get's really cold here.

 

You need to remove the dash, it's a pain but can be done. The trick is to work slowly. The procedure is covered in the workshop manual, it just looks much harder than it is.

Some points to note.

1) I'd suggest unlocking the steering wheel, and putting the car into "D" and opening the rear tailgate BEFORE you disconnect the battery (you will need to remove the passenger and driver's air bags so you MUST disconnect the battery-also note DON'T close the tailgate with the battery removed, you can't open it again!). This is mentioned in the workshop manual under the section on removing the driver's airbag.

2) You WILL need to remove the steering wheel as the lower dash bar won't clear it and will break (ask me how I know!, however it can be easily fixed once the car is disassembled if you need).

3) Putting the shifter into "D" will allow easy removal of the ash tray, A/C controller and ultimately the dash carrier unit. Put a thick sock over the shifter so you don't scratch it.

4) When removing the THOUSANDS of plastic trim clips, use 2 spatulas one on each side of the clip otherwise they just break off. I destroyed more than half of mine, but it still all went back together just fine.

5) Take note of the location of the middle BOSE speaker wire, it has a very tricky routing, the other speaker wires etc are fairly straight forward.

 

Now on RHD cars the right hand servo's are boxed in by the foot brake mechanism and holder (not a problem in LHD cars).

see http://www.specialistvehiclepreparations.com/blog/porsche-cayenne-heater-flap-replacement

 

I pondered this for a while as the above article says you have to remove the dash bar (which is basically impossible-I tried for about an hour to figure it out, but I couldn't budge it).

However you can save yourself a LOT of hassle by simply removing the foot brake mechanism!

It's actually very easy - again the procedure is in the workshop manual.

1) remove the metal "shield" from the top of the assembly (1 bolt and wiggle the shield up and through the wiring)

2) remove the brake light switch (one little bolt).

3) remove the 2 M8 bolts from the assembly (Not the big black on in the middle).

4) remove the pedal gas strut - good time to replace it..

5) wiggle the assembly up and out of the hanger. - I basically just hangs there on a hook setup, you may need to give it a little "tap" with a hammer to remove and also to re-seat it on re-assembly.

There is NO need to unclip the brake cable or the release cable, there's enough slack to simple push the assembly out of the way.

 

You can then get to those pesky servo motors quite easily using the tool similar to the one in this thread...

http://www.clubtouareg.com/forums/f73/hvac-flap-motor-replacement-dash-removal-185361.html

 

Note that Durametric CANNOT place the servo motors into service position (if they're broken then they won't move anyhow) so when you replace the motors, make sure the little arms engage with the white plastic flap arms.

Also check the flaps move freely before fitting the new motors, for good measure lubricate the arm pins with Porsche "liquid gold" or any other white lubricant.

 

The whole job took me about 5 hours to disassemble, 3 hours to replace the motors (most of that was actually trying to work out how to do it), and about 4 hours to put it all back together.

I could do it in half the time easily now, but hopefully I'll never have to do it again.

Cheers from Perth!

DS

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  • 6 months later...
  • 1 year later...

It seems this is happening to our 2006 Cayenne S, normal heat on drivers side but cold on passengers vent/floor/windscreen.

I purchased an aftermarket servo motor, but I can't tell which motor is the one to replace. Any help? It's not clear in the service manual.

And, have anyone found an easier way to get this done?

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