A5 Climatic and Climatronic Air Conditioner AC and Radiator Condenser Fan

DanG144

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Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
MkV MKVI AC Climatic and Climatronic Air Conditioner AC and Radiator Condenser Fan

Update:
I have appended a section on fan troubleshooting. It is actually for a Mk VI, but the steps for the Mk V are very similar, but the names in the measuring value blocks may differ slightly.

The A5's come with either Climatronic or Climatic (replaces manual, and is a simplified Climatronic.)

These compressors do NOT have an electric clutch, but rather a coupling with a break-a-way feature that is supposed to fail when the compressor locks up, so your serpentine belt does not break (and perhaps ruin your timing belt.) Make sure the center shaft of your compressor is turning before doing any other troubleshooting.

The compressors have an electric valve (N280) Refrigerant Control Valve (RCV) which controls the compressor's variable displacement based on evaporator temperature. This is as opposed to the mechanical valve inside an earlier (A4) compressor. Of course there are what appear to be dozens of interlocks and control override features to complicate the picture - but they can be checked with VCDS.

The N280 RCV is prone to sticking. VW says the only fix is to replace the compressor, but many people have been able to replace them easily and successfully . The symptoms of this is greatly delayed and erratic cooling from your AC system with all other things being healthy, or simply no cooling.

The fans on the A5 are unfortunately no more reliable than the A4 fans have proven to be.

The fans on the old mk IV manual AC system should start in slow as soon as the AC was asked to turn on, it did not matter if the clutch engaged or not.

The fans on the MkV systems must see AC pressure rise to over about 140 psi before they come on in the AC mode.

Luckily there are very good troubleshooting aides for the Mk V system built into its controllers - a VCDS is invaluable.

Fans - Go into the Engine Controller, OUTPUT TESTS, and choose the one for fan testing circuit one (on BRM engines you must choose sequential tests, and start with the engine running, then go through the test sequence until you reach the fan test - note - expect your engine to die at the ASV closure test; do not restart it, just keep going through the test sequence). This should cycle BOTH fans from off or very low speed to full speed in a periodic cycle.

The fan controller is built into the large fan on these cars. It develops the pulsed power signal that drives both the large fan and the small fan; because of this both fans should always turn at the same speed.

There is another test in this module for the AC system, but it is of minimal value. It calls itself AC clutch relay control circuit test, but don't be fooled - your compressor has no clutch. It does test that the ECU can tell your compressor to unload. If you run this test, do so on a warmed car, and watch for the changes in fuel as the compressor is allowed to load and unload (on some models you can see the pressure cycle as well). Have the AC on, engine on and warmed, AC demanded full cool.

Then go to the AUTO HVAC controller ADV Measuring values:
Choose
refrigerant pressure
Air-Conditioning Operation information
Compressor Shut-off Requirement
compressor current, specified value
Temperature after evaporator
Blower temperatures (there may be one, there may be half a dozen, look for all the one's that are in your selected blower path.)
Ambient temperature

Look at these closely.
If you have .825 amps or so requested current that is max. The refrigerant pressure should be high, and the temperature after the evaporator should be low -2 to 4 C or so. Check the blower temperatures (if any are available) as well. They are typically 2 or 3 degrees warmer than the evaporator temperature.

A bar of pressure is roughly 15 psig, so you can do the math ( or go to a units conversion site on line and let it do the math for you) to see if your high pressure sender agrees with your mechanical gauge set.

If anyone figures out the details on the basic settings tests and the Output tests for the AUTO HVAC module, please post them in this thread.

The compressor shut-off requirement is the status of the interlocks, and can tell you what may be preventing operation. As long as it says "no shut-off signal is present" and your current is high, then the pressure should be high and the temperature after the evaporator is low. If the pressure is low (and you have a good charge in the system) then the RCV is probably bad. Do verify that the compressor is turning, which it must be unless the break-away protective system has broken free.

The most common failure on these cars AC system is the RCV, Refrigerant Control Valve built into the compressor.
Next is probably the fans.
Then the high pressure sensor.

AC Compressor Refrigerant Control Valve Make sure you get the proper valve for your compressor.

Some AC shut-off codes:
A/C cut-off Codes
0 = Compressor on (no shut-off requirement of the A/C compressor detected)
1 = Compressor off (refrigerant pressure was or is too high)
2 = Compressor off (blower motor circuit)
3 = Compressor off (refrigerant pressure was or is too low)
4 = Compressor off (display not currently intended)
5 = Compressor off (no engine start or no engine speed detected)
6 = Compressor off (A/C system switched off, ECON-mode activated)
7 = Compressor off (A/C system switched off, blower switch in position 0)
8 = Compressor off (outside temperature was less than 1.5°C and is still less than 2.5 °C)
9 = Compressor off (display not currently intended)
10 = Compressor off (Low voltage)
11 = Compressor off (display not currently intended)
12 = Compressor off (shut-off request from Engine Control Module (ECM) via CAN)
13 = Compressor off (voltage supply terminal 30 too high)
14 = Compressor off (Evaporator Temperature)
15 = Compressor off (display not currently intended)
16 = Compressor off (activation A/C Compressor Regulator Valve -N280- implausible)
17 = Compressor off (no signal or implausible signal from High Pressure Sensor -G65-)
18 = Compressor off (engine speed too high at standstill)
19 = Compressor off (shutoff request from Vehicle Electrical System Control Module via CAN)
20 = Compressor off (refrigerant loss-currently V8 Touareg only)
21 = Compressor off (Outside Temp < 2 degrees C, without recirc mode on)
22 = Compressor off (Outside Temp < 2 degrees C, Inside Temp. < 10 degrees C)


Here is a list of typical Compressor Shut off codes from ROSS-TECH (VCDS folks):
(This list may vary form vehicle to vehicle, so check your repair manual or Measuring Value Block pop-up)
- 0 = Compressor ON
- 1 = Compressor OFF: Refrigerant Pressure too high (> 32 bar)
- 2 = compressor OFF: Basic setting not performed
- 3 = Compressor OFF: Refrigerant Pressure too low (< 2.0 bar)
- 5 = Compressor OFF: Engine Start Detection
- 6 = Compressor OFF: ECON Mode active
- 7 = Compressor OFF: A/C System / FAN OFF
- 8 = Compressor OFF: Outside Temperature too low (< 3.0 °C)
- 10 = Compressor OFF: Vehicle System Voltage too low (< 10.1 V)
- 11 = Compressor OFF: Engine Temperature too high (> 118 °C)
- 12 = Compressor OFF: Shut-Off requested by Engine Control
- 13 = Compressor OFF: Vehicle System Voltage too high (> 17 V)
- 14 = Compressor OFF: Evaporator Temperature too low
- 16 = Compressor OFF: Compressor Activation faulty
- 17 = Compressor OFF: No or implausible Signal Pressure Sensor
- 18 = Compressor OFF: Vehicle Speed Shut-Off
- 19 = Compressor OFF: Shut-Off requested by Central Electronics Control (Load Management)
 
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DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Climatic fuses and info
DanG144 said:
I borrowed a manual last night. Bentley Service Manual 2005, 2006, 2007, 2008. Editorial closing 2/2008.

Controls
SA6 fuse 6 on panel A
SC4 fuse 4 on panel C
SC16 fuse 16 on panel C
SC40 fuse 40 on panel C
SC 46 fuse 46 on panel C

Fans
SA1 200 amp Fuse 1 on fuse panel A (may appear as a solid wire, probably it is a fusible link - this is main power in to the fuse panel A from the alternator.
SA3 50 amp fuse 3 on fuse panel A
SB24 10 amp fuse on fuse panel B

Fuse Panel A and B are located engine compartment left (looks to be outboard the battery), B is the top surface with low amperage fuses, A is the front surface with high amperage metal strip fuses.

Fuse panel C is outboard on the left side of the dashboard.

Some of this control power comes through the J317 power supply relay

You do have two fans up front, right? Engine code BRM? If not, then the fan fuses differ.

The location description for J301 (the Climatic system A/C system and heater control module) is "A/C and heater control panel in center dashboard". It is NOT shown on the referenced figure.

It looks to have 3 connectors on it, a 5 pin, a 16 pin, and a 20 pin. It is too big to be mounted in a relay panel, in all likelihood.

The fans should be turned on, via the ECU, when the G83 radiator temperature switch actuates.

It looks as if all the fan commands come from the ECU. So even the AC controls have to send signals to the ECU when it desires the fans to run.
The fans turn on when pressures exceed about 8.8 bar or 130 psig.
 
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DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Quite a few people are having problems with delayed starts on their A5 air conditioning systems, both Climatic and Climatronic.
There is not a delay relay as is used on certain Passats.
The controls do have the ability to delay compressor loading for up to (at least) 4 minutes. This delay appears to be variable and programmed in based on last operation, down time, ambient conditions.
But many people are still seeing delays beyond this. At least some of these delays are due to the N280 control valve sticking.
This delay is best seen by logging some VCDS parameters on startup after being off overnight.

One member pointed out this source of information about shutdown codes.
 
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DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
This is a string of recent PMs.
f1wanabe said:
Hello Dan,
My fans are not working and I have no A/C on my 2006 tdi. I have the manual A/C system & fans do not work when key is in on position or when car is running. I can see 2 mounting bolts for the right fan, is there a third below? Are there three for the left one? Do you have tips for removing the fans on a 2006? I would appreciate any pointers.
Thanks for your article- its very helpful.
-Greg
DanG144 said:
Greg,
Your fans only come on when the AC system high pressure is reported to be high enough to warrant their operation. This is about 8.8 bar or about 130 psi, which is equivalent to about 105 degrees F. So when your condenser outlet line (the one with the filter drier in it, and the schrader valve for hooking up the pressure gauge) gets too hot to hold for 5 seconds, then your fans should be on.

Typically this is within one minute of AC operation at temperatures where anyone is concerned about the AC.

Your "Manual" system is actually called Climatic, and is not the manual systems referred to on the A4's. (Unless it is different than any other A5 I have examined.)

Does your AC function at all? When the car is going down the interstate?

If your AC compressor is not functioning, then you will have to test your fans some other way.

To answer your original question. Each fan is held in place by three bolts, one at the end of each spider leg support.

The large fan contains the fan control module (which is actually only a fan control module on your car - controls nothing else) and provides electric power to the smaller fan. Unfortunately this controller is a high failure rate item.

You can test your smaller fan by providing power to it directly, putting 12 volts down the two power lines.

The easiest and by far the best way to test these systems is with a VCDS system. The output tests on the engine and the 'auto HVAC" modules test the fan operation.

VCDS is also the best tool to help troubleshoot your system.

Would you mind if I posted this conversation? Others need to read it.

I hope to be posting something in the A5 forum soon on AC and fans.

If you can get to a VCDS (remember you need one that has CAN in the name), and need some help using it and interpreting it, give me a call. I am not far enough along to have valid written instructions yet.
f1wanabe said:
Thanks for the reply, Dan.
I normally do post in the forum- I don't know why I didn't this time. Feel free to post it. The a/c did work once the car was moving, then would get warmer at traffic lights. However, ona 60 mile trip to the airport last week, it worked only for 20 min or so. I will do a direct voltage test, then explore the VCDS testing. I look forward to your post, and will keep you informed.
-Greg
DanG144 said:
This does sound as if it started out as a fan problem. You are likely to find the controller is bad on your large fan.

It may have developed other problems though, due to the high pressures and temperatures at which it was operating.

Holler if I can help.

Dan
f1wanabe said:
Hi Dan,
Pls. let me know in what thread you would like me to post. But, After driving this am, this is what I found. Large fan works and varies between slow an fast operation. Small fan does not work- I will do a direct voltage test today. I noticed that when outdoor temp exceeded 80F the a/c goes warm. Under 80 F it is much cooler. On the highway A/C was better than in town. I assume that if the small fan were running the cooling would be much better.
Thanks,
Greg
DanG144 said:
Greg,
You are correct about the AC working better with both fans.
I would still get a VCDS checkout on your AC when you can.
You have about an 80% chance that the small fan can be repaired by the instructions in the A4 fan repair pdf.
The A5 fans are pretty expensive right now. Let me know if you find a good source for them. A friend paid $120 for a small A5 fan on the internet 6 months ago. You can buy both A4 fans for this amount.
Keep an eye on your large fan, it is liable to be intermittently operating.
Your fans are completely variable in speed; they do not just have slow and fast.

I will start a post. In the A5 forum some time today and let you know.
Dan
 
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dgetta

Active member
Joined
Mar 18, 2009
Location
nj
TDI
2005 getta
Dan with all of your research have you found any problems with worn wires and shorts in the system ? I have a 05.5 mk5 Jetta and right now I'm having all kind of problems with the air. Right now there is no fan, no air , no heated seats and I keep blowing fuses on the SC4 circuit . I've disconnected every function on the circuit one at a time and blow fuses all the way . Ever heard of such a thing ? I've got my scan codes on the thread "learning Vag Com" and or 'still learning Vag Com".
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Wiring with insulation fretted through are common problems on these cars.

Try examining the wiring going to the connectors, opening the split looms. It is pretty easy to do, and often very easy to find the problem. If you see a sudden direction change on the loom, like at a clamp, that is the place to look the closest.
 

dgetta

Active member
Joined
Mar 18, 2009
Location
nj
TDI
2005 getta
Dan I have eliminated the wire that connects to the A/C regulator valve. I disconnected that on the other side of the radiator area. That wire had continuity so after disconnect the wire that continues toward the fuse box area seems to be OK ; but I'm still blowing fuses. Where the harness goes thru the firewall isn't easy to follow. would you know where I could find a different wire schematics than the Bentley I seem to be having trouble reading these or the colors are different than what I'm working on.
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
https://erwin.vw.com/erwin/

Erwin is the only other source I know of for diagrams. They look the same as the ones in the Bentley, but have updates and options.

You might get one exactly for your car.

You pay by the hour or the day for access.

Be sure you get the USA version, and you get VW not AUDI. Have a good printer handy with lots of ink and paper.

When you are checking your wiring, check for undesireable/inadvertent grounds as well as continuity.

Often visual inspection, opening the looms, is the best way to find problems.
 

dgetta

Active member
Joined
Mar 18, 2009
Location
nj
TDI
2005 getta
I looked at Erwin, it's a shame they don't let you look at an example they offer before you buy. I'd like to know I'm getting something more informative than what I already have before buying. Anyway thanks for the source , I'll probably look into it further Wed. I have to try to trace blk/blu wire from the fuse box to the ECM. Are there any anti- static precautions I should take before getting my hands on this? Should I wear latex gloves? Thanks
 

Clark20ry

Active member
Joined
May 9, 2007
Location
Phoenix AZ
TDI
2006 Jetta
Ok I am going to add to this thread. Do they make a replacement fan control module? or do I have to replace the whole fan assembly....?
 

Sootman

Veteran Member
Joined
Jan 30, 2003
Location
Maine Coast
TDI
2011 Golf TDI
On my late '06 I found the smaller fan does not work. While changing my clutch I had the guys at the shop pull the fans (easy with the transmission out) and opened up the cover on the small fan after trying to apply 12 volts directly and not having the fan start. One brush was not touching the commutator. I was able to wiggle it and have the brush move back into position but still no luck getting the fan to work. We were pretty busy with the transmission so I gave up on the fan. I'm going to try and pull the fans again tomorrow and see if I can clean and re-check the brushes, resistor and what ever else is in there. I will try to post some pictures if they look different than those you posted Dan in your A4 thread.
 

Sootman

Veteran Member
Joined
Jan 30, 2003
Location
Maine Coast
TDI
2011 Golf TDI
CAUTION…long description. Also I blew it on the pics.
Well I decide to tackle fixing the small fan today like an idiot as the temp is in the high 80's and the humidity is similar. On the A5 there are no doubt some subtle differences between it and the A4 but in general it seems pretty similar. I began by removing the cover of the air intake (located in front of the air box containing the filter). The top snaps off then I removed the curved tube connecting this intake to the filter box. Finally I removed the 2 #20 Torx screws holding the piece that mounts to the grill. I was trying to get some room to reach the #30 Torx screw holding the upper driver’s side of the fan housing.
The next thing I found was a coolant hose in my way to reach the upper driver’s side #30 Torx. In an ideal world I would have had a ¼” drive #30 Torx bit or a right angle bit, but I had to make due with the 3/8” drive I had available. I decided to remove the coolant hose and hoped I wouldn’t loose too much coolant. I pulled the clip on the hose and was able to remove the hose without loosing much coolant at all; although it did make a bit of a mess. After some work I was able to remove the driver’s side Torx screw. It was a PITA.
One down 3 to go I figured I had the tough screw done, but the screw on the passenger’s side wasn’t much easier. An air conditioning hose was blocking easy access to this screw. It took awhile but by applying pressure toward the fender on this hose I was able to get my Torx bit in place. Here again a nice ¼” bit would have been great. I’m going to go look for one this week. After some effort I was able to get this screw out. 2 more to go!
I jacked the car up and put it on stands. Then pulled the bottom sound-absorbing panel with it 20 something screws (OK maybe there aren’t 20 but there’s a bunch of ‘em). I pulled the lower intercooler hose, disconnected the power plug to the fans and was able to reach the last 2 Torx screws with less effort than the top 2 screws. The next trick was to pull the fan unit out. After a lot of wiggling, yanking, tipping and a bit of swearing I was able to pull it out from the bottom. Once out it was easy to disconnect the small fan’s plug and the remove the 3 bolts that hold the fan in the housing. As I had already ground off the tabs as descried in the A4 thread I separated the housing. I could immediately see one of the brushes was not contacting the commutator. I removed the brushes and soaked everything down with DeoxIT as this is my favorite electrical cleaner. I used some #800 grit sandpaper that was wetted with DeoxIT and cleaned all sides of both brushes to make sure they were smooth. I also used this sandpaper on the commutator spraying it with DeoxIT both before and after sanding. I then liberally sprayed the whole area just for good measure. After reassembly the fan ran full speed with 12 volts applied to the connector (small fan connector). I was never able to make either fan work by applying 12 volts to the connector coming from the large fan.
I reassembled the whole thing and neither fan worked. I was pretty unhappy, but then remembered I may not have plugged in the big connector under the car. Got the car back up in the air and pull the sound-absorbing panel again and there were the 2 pieces of the connector not snapped together. Put the connector together and bingo, 2 fans now working just as they should. They start slowly at first and speed up as the AC demands more cooling.
Thanks Dan for starting this thread (and the A4 too) as I otherwise would have had to go to the dealer and spend the big money. The small fan is noisy so I’m going to see if I can find a new replacement, but at least I’ll have a better chance of doing it correctly (and hopefully much quicker) next time.
 

RonP

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Joined
Apr 16, 2008
Location
Orillia, ON, CA
TDI
2003 TDI ALH 2006 TDI BRM
Many many thanks Dan for all your background info on the AC system. Your posts helped me to resolve both my pressure sensor problem and repair the small fan (one brush seized with dirt). Resistance across pins showed open circuit. Once repaired resistance was 0.6 ohms. I owe you a cold one!

The fan repair pdf should be added to the DIY sticky. Likewise for frequently checking for proper fan operation. I was not checking AND I had no idea that both fans should be running together at all times.
 

Clark20ry

Active member
Joined
May 9, 2007
Location
Phoenix AZ
TDI
2006 Jetta
Well I just replaced mine today... I was able to just buy the small fan with out having to do the whole assembly with both fans. I got the fan from Exclusive for $190 seemed fair. The whole project took 45 minutes with doing the fuel filter while I was under the hood. Seems to work good blows ice cold. The car still takes a minute after I start it up to start cooling. My wife says it has always done that...
 

Rob71zilla

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Joined
Mar 17, 2011
Location
Fayetteville, NY
TDI
2010 Jetta
I tried using my AC for the first time today (I've only owned the car for 2 months) and it blows plenty of air but it's never cold. Just a little cooler than warm at best. I had it on for my entire 75 miles trip and it never changed.

Do you think it could be because of the fan issue or something else? Like I said the vents have plenty of air being pushed out of them just not cold at all.
 

Rob71zilla

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Joined
Mar 17, 2011
Location
Fayetteville, NY
TDI
2010 Jetta
Will a recharging kit from an autoparts store work for our cars? Sorry if that's a dumb question....I've never used those things before
 

pawel

Veteran Member
Joined
Apr 19, 2008
Location
Naugatuck, CT
TDI
'09 TDI 6 MT, Platinum Gray Metallic, Anthracite Interior
The numbers specified on the recharge kits are wrong for our cars.
It can be dangerous to use only one of those kits.
So what are the correct numbers then?
We are talking about pressure? Right?
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
The simple single-pressure-gauge addition kits measure only suction pressure; they ignore discharge pressure. This makes no sense at all on our systems which control suction pressure to certain values (I do not have the references with me.) The suction pressure has absolutely NO correlation to the amount of refrigerant in the system.

If you try to follow the instructions on many of the kits, you will take the high side (compressor discharge) to a solid refrigerant condition, and either shut off the compressor due to overpressure, or blow the safety valve, or (if you are really unlucky) blow up your compressor. People on this site have done all three things to their systems.

The only real way to put the correct charge in a system is by weight, starting from empty. A poor second method is to monitor the discharge pressure and suction pressure while adding a small amount of refrigerant.

Our systems will typically cool very well with only 20% of the normal charge.

Many people start adding refrigerant, feel the additional cooling from the liquid freon in the can, and think that they are on the right track - it is getting cooler as I add - so if it does not cool as well as I think it should, I should just add more refrigerant. They add until something quits.

There are many sad tales about this on this site alone.
 

DanG144

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Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
blown up compressor

The simple single-pressure-gauge addition kits measure only suction pressure; they ignore discharge pressure. This makes no sense at all on our systems which control suction pressure to certain values (I do not have the references with me.) The suction pressure has absolutely NO correlation to the amount of refrigerant in the system.

If you try to follow the instructions on many of the kits, you will take the high side (compressor discharge) to a solid refrigerant condition, and either shut off the compressor due to overpressure, or blow the safety valve, or (if you are really unlucky) blow up your compressor. People on this site have done all three things to their systems.

The only real way to put the correct charge in a system is by weight, starting from empty. A poor second method is to monitor the discharge pressure and suction pressure while adding a small amount of refrigerant.

Our systems will typically cool very well with only 20% of the normal charge.

Many people start adding refrigerant, feel the additional cooling from the liquid freon in the can, and think that they are on the right track - it is getting cooler as I add - so if it does not cool as well as I think it should, I should just add more refrigerant. They add until something quits.

There are many sad tales about this on this site alone.
 

pawel

Veteran Member
Joined
Apr 19, 2008
Location
Naugatuck, CT
TDI
'09 TDI 6 MT, Platinum Gray Metallic, Anthracite Interior
So you are not advising on using full gauge set (low, high pressure gauges, charge/discharge port) to top of the system while monitoring both pressure values?
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Whenever you are adding freon you need both gauges, High and low pressure. I would never add without them both.

What I am saying is that even with those gauges you can still overcharge the system.

The low side pressure will be controlled by the compressor. The high side pressure is determined by temperature - right up until you "go solid" - get pure liquid with no gas space left. When that happens pressure spikes so fast that you cannot respond.

You are supposed to put a certain mass (or weight) of refrigerant in your system - any more and you may go solid on your high side under certain conditions. So the only proper way to fill your system is to evacuate it and then add a certain number of grams or ounces of refrigerant (and the proper amount of oil.)
 

Diesel Larry

Active member
Joined
Jul 27, 2008
Location
Sarasota, FL
TDI
'09 Jetta
Quite a few people are having problems with delayed starts on their A5 air conditioning systems, both Climatic and Climatronic.
There is not a delay relay as is used on certain Passats.
The controls do have the ability to delay compressor loading for up to (at least) 4 minutes. This delay appears to be variable and programmed in based on last operation, down time, ambient conditions.
But many people are still seeing delays beyond this. At least some of these delays are due to the N280 control valve sticking.
This delay is best seen by logging some VCDS parameters on startup after being off overnight.

One member pointed out this source of information about shutdown codes.

Why in the world is there programming to intentionally introduce a 4 minute delay in compressor loading, when the car has been sitting for at least 8 hours? For the last few weeks, this 4 minute delay has been going on with my Jetta. It is not pleasant to experience 90+ degrees. One day I think the air coming out of the vents actually got hotter for a minute or two. A trip to the dealer (warranty work on door lock) revealed nothing... they said the temp. difference was 30 degrees, so all was well.

Having a 4 minute delay, when it is hot out, is unacceptable. Oddly enough, I didn't experience this last year. Also, my friends 2006 Jetta's A/C seems waaaay more potent than mine could ever wish to be. - it will actually give you an ice cream headache the air is so cold. Mine? .. it might give a fly the same. (an older, more feeble fly).
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
I would bet that your delay is not due to the programmed delay, but due to a fault.

It would be nice if I had found a cheap, easy way to fix the delay. But I have not.
 

AndySRT

Veteran Member
Joined
Nov 30, 2010
Location
cary il
TDI
2010 cup car
on my 2010 the A/C just went out and we are having a heat wave here in chicago. luckily i am still under warrenty( dealer cant get the car in till tuesday tho) so i will report back on what the dealer says because mine seems to get hotter when i turn the fans on with the A/C button pressed and the knob turned all the way to cold.
 
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