car ac can be dramatically different from building hvac. what were the pressures he was reading from the car on the low and high side?

when you say the high side was cold, do you mean the fat pipe that was cold, or the skinny smaller pipe that was cold?

the skinny pipe has a smaller inner area because it's keeping it compressed. the low side will be a larger diameter pipe.

it also is very likely that the expansion valve has indeed failed. you won't really lose much by doing that job.

one thing to be SURE To do while there is replace the receiver drier, while you're at it.
as old as it is, if original, even if only half the age of the car... it's likely time.

 

I'll check after work and get back to you. Thanks for the assist. Fingers crossed-it's hot in TX!

 

it's hot in TX!

It's just starting to get warm

6A is the part and it's easy to replace once the system is empty.

 

Item 6A in your diagram is the expansion orifice, where the liquid refrigerant switches to a gas as it passes into the evaporator. Sipes216 mentioned changing the receiver dryer, however if the system has always been sealed from the outside air, there should be no reason to change it. The process of evacuating the system with a vacuum pump boils out any water that the desiccant in the R/D has.

 

OK, i've priced up the parts (may as well change the dryer?) The evacuate and refill is $150 locally. How do these expansion orifices fail? maybe the filter blocked somehow?

I think the correct side was getting cold (just after the orifice) but it wasn't extending into the cabin (maybe a flow issue?)

 

I worked on the AC of my BMW. It have the expansion valve instead of the expansion orifice. Once you drain the system, you can just replace it (6A/ orifice). It will get clogged from tiny particles. I see this on the expansion valve. Also check and see if the evaporator is not clogged. I guess you can blow air from one side to check this.

The service manual for bmw says, it the system is open for more than 24 hours, replace the dryer. I think the same rule applies here too.

If one line is cold, the refrigerant is expanding and the evaporator is cold. Any chance the hot air flap or that mechanism is opening up inside ?

Wonder if there is a way to read the Evaporator temperature using the VAG-COM. If you can, and it is close to freezing, then it should be the hot air making it less cold.

 

Drier and orifice replaced. Now to go get R134 and a vacuum pump to see if it works! I added PAG 46 (about 3 oz) into the drier before fitting. there was non in the drier when i removed it. There was evidence of oil on the orifice, so there is some in the system from previous.

Also found that my CV boot is split...

 

Vacuum carried out, recharged and tested. The orifice now has a definite hot/cold side to it now (the cold side is baltic cold!) At standstill i was getting around 24C/75F at the vent, driving gets 15C/60F.

It's currently 40C here and i can sit in the car without heat drama, so i guess it works!

EDIT:
OK, it's not the arctic i expected so i checked the Climatronic error codes. Showing:

4FA-Recirculation Flap Servo Motor
4F8-Central Flap Servo Motor
4F7-Temperature Flap Servo Motor
25B-Footwell/Defrost Flap servo motor

Anyone have a wiring diagram for the Climatronic? I reckon i'm not getting really cold due to flap positions. I've reset the codes to see what happens on the run to work tomorrow.

Wondering if there is a single fuse which provides power to the Climatronic/servos. I notice that these actuators are all on the same connector at the rear of the Climatronic head unit...

 

OK, time to wrap up.

Removed, fixed and refitted V71 Air Flap actuator after Climatronic code (only F4A) and no recirculate. Motor had stuck, just needed 12V applying to free up.

No dash removed

A/C now a Tsunami of cool air, Recirculate working fine. Happy Texas summer. Thanks for bearing with me, it's been emotional at times!

If it fails again, i'm not worried about removing the V71. It IS do-able without dash removal.

 

If you check the attached image identified as '15-Sinik regulacyjny', you can see where the upper white bracket screw mounts to the hi/low input to the evaporator. Remove this screw and the lower white bracket screw (not shown but easy to see when looking up from under the plenum) The V71 and white bracket should now come free.

NOTE:these screws are vertical. There is no need to remove any screws which are aligned 'across' the car.

Re-assembly was a matter of mounting the V71 to the bracket, line up door pins on the V71 cam, secure bracket and V71 assembly to the plenum with the two screws.

Image of bracket:

 

Did you have to remove the glovebox or anything else to get to this? Any chance you can give some steps on remove/replace? I have almost the exact same issues as you.

 

First write up and i apologise for lack of pictures.
This was on my B5.5 V6 30V with Climatronic.

1. Remove the glovebox (many torx screws)

2. Remove the blower fan (three torx screws)

3. Lying upside down, looking up, electrically disconnect the V71 actuator.

4. looking upwards you will see two vertically aligned screws-these hold the white bracket in place on the plenum body (both circled in red on the attachment below:

5. Undo these two torx screws and the actuator and bracket should come away as one piece

NOTE 1: The cam on the actuator engages two pins on the recirculation doors (one pin on an inner track, the other rides around the outside of the cam when the recirculate doors are set to 'outside air'. Take note of this for installation of the actuator assembly onto the plenum.

6. When the actuator is removed, reach in and check the recirculation doors can move freely, if they rotate freely continue to step 7, if not rectify mechanical issue.

7. Electrically reconnect V71 and perform the Climatronic self test (ignition set to 'on' pressing 'econ' and 'recirculate' for >2 seconds) This 'should' motor the V71 and all other actuators. If it doesn't move, you can replace the V71 at this point.

8. If the V71 actuator has not moved under Climatronic test, remove V71 from the white mounting bracket (3 torx screws) and either replace with new actuator or take apart to check gears/remove the motor to test on a 12V battery.

NOTE 2: I tested the motor and reassembled the actuator, electrically connected and ran the Climatronic test. It worked so i rebuilt the actuator/bracket assembly and installed onto the plenum. Climatronic test carried out again and it worked-Your Mileage May Vary...

9. Reassembly is the reverse-noting the pin/cam locations as per NOTE 2.

Good luck, it can be done.

(I started out trying to undo all the Torx i could find, It turns out there is a hex on them also, it is a 5.5mm. It was useful to get to the awkward ones. It was at this point i found that only two hold the assembly to the plenum...)

 

FYI: Climatronic servo motors run on 5 Volts.

 

I believe the motors run on 12 volts.

Indeed, there is a 5 volt, 10 mA, power supply (from the head unit) for the potentiometers that provide position feedback, thus the potentiometer wiper voltage varies from 0 to 5 volts as the damper position changes. But I'm nearly certain the motors themselves are 12 volts.

 

Ooops! Well, 12V works well for fixing them ;-)

 

That is correct, 12V motors 5V sensors.

 

awesome - thank you!

 

Thinking about it, i wonder if you could just leave the V71 in situ and apply 12V to the correct pins on the electrical connector of the actuator? It would achieve the same aim. You'd have to be careful not to overdrive the motor with the cam in the end stop positions, but could be an even quicker fix.

The risk would be ruining the motor when it reaches its end stop as there will be no positional feedback.

 

FrescoGreen - do you know how to test the Climatronic head unit to see if the 5 volt power supply is functioning or what gets messed up on them? I've been reading your many posts referring to the issue of having the 4 error codes and that being caused by a bad 5 volt power supply. I looked into replacement head units and the used ones are cheap enough but there's no guarantee they aren't dead as well. As you probably know the OEM one is quite expensive. I wonder about disassembling the head unit and replacing what ever faulty component is in there?

 

Testing for the 5 volt signal is technically easy--just connect a DC voltmeter. Practically, it might be a bit of work, but I've not had to try it.

The 5 volts exists at each of the flap potentiometers. There may be one that's accessible, perhaps with glovebox removal. Brown/white is signal ground, red/yellow is 5 volts. 5 volts should be present whenever the Climatronic is powered up.

You could also measure at the rear of the Climatronic head unit, presuming the wires are long enough (I don't know). The brown/white signal ground is on pins 9 & 12 of the 12-position black connector. The red/yellow 5 volts is on pin 8 of the brown 16 pin connector.

I would think the 5 volt regulator (all of 10 mA) could be replaced if necessary, but at that capacity it's probably a small surface-mount part, so you might need a magnifying glass. If you crack a Climatronic open and find the regulator, please post photos.

Reference Bentley, schematic 33, and pages V87-23 & -24.

 

Since refit i've kept an eye on the recirculaton position with the Climatronic OBD mode. There's a lot of hunting going on at an 'upper/mid' position (around 200). Fully recirc shows as 25 and open to outside air is 230 ish.

I think it's probably the position feedback pot in the V71. When i feel inclined i may pull it again and clean the potentiometer up (if i can).

EDIT: I pulled the V71, took all of 30 mins from glovebox removal to V71 out and opened up. Cleaned the potentiometer and it seems to be stable under OBD testing. I'll update this post when i've driven for a while.

 

Does anyone know if the free VCDS reset the positions of the actuators?

The cleaning of the potentiometer has stopped the hunting of the V71 actuator I just want to make sure the end points are set correctly.

 

Not sure about unregistered VCDS-Lite, but this will.

See this Self diagnostic test. (Read second paragraph before using)
http://www.saunalahti.fi/~jues/Climatronic_Self_Diagnostics.pdf

NOTE: Actuator test: Requirements: Should read;
“Ignition off, Motor off, Vehicle stopped, Battery Voltage >11.5 <15.5V.”

 

Ah, OK thank you. I've done that but didn't realise it would zero the end points.

Thanks for the quick reply.