Climatronic Not Cooling: Troubleshooting Guide

Hello everyone,

Even though this topic has been discussed several times before, I haven't been able to find a solution or idea to address my problem.

Regarding the car:
I drive a VW Golf IV TDI Variant, 66 kW, with Climatronic, manufactured in May 2000, with a mileage of 109,000 km.

Background:
I bought the car in October 2003 (mileage 95,000 km) -> Complete service history.
At that time, I couldn't properly test the Climatronic system because the temperatures were quite cool, but it never produced really cold air (in AUTO and LO modes), unlike my old manual climate control system in my Golf III.

Regarding the issue:
Since the temperatures are rising again (up to 20°C), I've been playing around with the climate control system, but I'm not getting any cool air (it's only blowing air around the outside temperature).

Regarding the troubleshooting performed so far:
Climatronic error codes are not being displayed (444).
Recently, everything was checked with the VAG-COM diagnostic tool at the mechanic's shop, and no errors were displayed (after replacing the mass airflow sensor).
When switching from ECON to AUTO mode, the engine speed drops slightly, and the headlights dim a little (indicating a load), but no clicking sound from the solenoid valve can be heard (with the hood open).
The two hoses on the passenger side that run from the engine compartment into the interior (one thick and one thinner) do not get cold; they are rather warm to hot (since they are part of the air conditioning system).
A pressure test has not yet been performed.

My theories:
No clicking of the magnetic clutch -> insufficient coolant, which contradicts the decreasing speed observed when the system is turned on.
Faulty solenoid valve -> however, this contradicts the decreasing speed when starting, unless the valve is constantly closed.
Compressor malfunction.
Pressure sensor malfunction.
However, I don't know exactly which error codes will be displayed (if any) if one of my theories is correct.

Maybe someone else has experienced similar problems and can offer some advice before I take it to the workshop and spend a lot of money.
'Is there perhaps anything that can still be done under warranty (4 years old, complete service history with VAG), or with the dealer where I purchased the vehicle (who is not a VAG dealer)?'

Hello,

'I had a similar problem with my Golf IV. After turning on the air conditioning, the compressor would engage (the engine speed would decrease slightly), but only warm air would come out. In my case, the expansion valve was defective.'
The workshop then replaced the dryer and refilled the system with new refrigerant.

Best regards,
Frank.

Hello,

'I had a similar problem with my Golf IV. After turning on the air conditioning, the compressor would engage (the engine speed would decrease slightly), but only warm air would come out. In my case, the expansion valve was defective.'
The workshop then replaced the dryer and refilled the system with new refrigerant.

Best regards,
Frank

Hello Frank,

Was there an error code?

What did all of this cost?
You often read about shockingly high numbers when it comes to repairs on air conditioning systems.

Hello,

I'm not entirely sure how your compressor looks. However, on mine (a Golf 3), you can see whether only the pulley is rotating, or whether the magnetic clutch is working and the entire compressor is spinning (take a look at the compressor's shaft). If you could take a look at yours and let us know what you see, it would help us to assist you better.

Since you're mentioning a drop in RPM, I assume the magnetic coupling is functioning correctly (but please check that!). Therefore, there's likely a defect in the coolant circuit that isn't electrical in nature. Since the coupling shouldn't activate with insufficient pressure (pressure sensor), the coolant level should also be correct. I suspect a problem with the throttle or expansion valve, but I'm definitely not a climate control specialist.

Take a look at the technical article about the air conditioning system here in the forum /viewtopic.php?t=3475; it explains everything very well, and it tells you where you (or someone with appropriate measuring equipment) need to look.

Regards,
Private.

Hello,

I'm not entirely sure what your compressor looks like. However, on mine (a Golf 3), you can see whether only the pulley is rotating, or whether the magnetic clutch is working and the entire compressor is spinning (take a look at the compressor's shaft). If you could take a look at yours and let us know what you see, it would help us to assist you better.

Since you're mentioning a drop in engine speed, I assume the magnetic clutch is functioning correctly (but please check that!). Therefore, there's likely a problem in the coolant circuit that isn't electrical in nature. Since the clutch shouldn't activate with insufficient pressure (pressure sensor), the coolant level should also be correct. I suspect it might be the throttle or expansion valve, but I'm definitely not a climate control specialist.

Take a look at the technical article about the air conditioning system here in the forum /viewtopic.php?t=3475; it explains everything very well, and you'll know where to look (or where someone with appropriate measuring equipment needs to look).

Regards,
Private

Hello,

I took a look at the compressor, but I couldn't tell if it was running (it's quite cluttered in that area).
However, I noticed that when the air conditioning is turned on, both radiator fans start up (which could indicate a drop in engine speed).
As I said, there is absolutely no clicking sound from the magnetic contactor.
I wanted to check the fuses, but I couldn't figure out which fuse is responsible because the symbol from the manual (a snowflake) wasn't on the label inside the fuse box cover. Nor was there anything similar.
Perhaps someone can help me figure this out (fuse number / amperage)?

"If the air conditioning pipes are getting warm to hot, that's a good sign. Turn your refrigerator around and place the back of it on the heat exchanger; it's definitely warm there. That's the principle of how air conditioning works. You use a refrigerant, pressurize it, send it through a vaporizer, and use the vaporization heat (cold). It draws the heat out of the incoming air, and that air is then transported to the radiator at the front and back to the compressor, and the process repeats."
Okay, in my Golf (ASZ), you can't tell if the compressor is spinning or not. The simplest trick is this: start the car, have someone switch from "econ" mode to "auto" mode, and while you're doing that, put your hand on the compressor (be careful of the belt and the fan starting up). If it's not working, it will almost certainly throw a fault code. I'm initially suspecting a lack of refrigerant!

Hello Diesel-Kai,

The replacement of the expansion valve and the dryer, including the refrigerant refill, cost approximately 300 EUR.
Unfortunately, I don't know if there was an error code.

Best regards,

Frank.

Hello,
Therefore, something in the coolant circuit is likely defective, and it's not of an electrical nature. Since the clutch probably won't engage with insufficient pressure (pressure sensor), the coolant level must also be correct.


The information about the filling amount is not entirely correct.
Often, there is still enough capacity within the system for the pressure switch (so it doesn't shut off due to 'low pressure'), but not enough remaining to 'cool' the system.
The easiest thing to do is to have the pressure measured.

Hello, it's not necessarily true that the pressure will be lower if there is too little coolant in the system.
Therefore, a pressure test is of little use.
It's best to completely vacuum the system to see how much refrigerant was still inside, and then refill the system with the correct amount.

So, I've experienced something new again:

I went to the 'Friendly' service center today to have my air conditioning system refilled, and thankfully, I stayed there the whole time.
The estimated cost for the phone consultation was €25 for labor, €30 for approximately 1.3 kg of refrigerant, and €7 for 0.3 liters of compressor oil, totaling €62.


The compressor was already running in the other car and hadn't been drained, so we agreed on a fill amount of 50ml of compressor oil (based on the experience of another technician).
The facility was evacuated for 45 minutes, etc.
Then the mechanic added 0.8 kg of refrigerant, sealed everything up, started the car, and within 5 seconds he said the air conditioning would be working, and he drove the car out of the garage.
Hmm... I've been thinking about this, because I seem to recall hearing something about 1.3 kg of refrigerant.
Well, let's go pay, and the master technician has 96.xx euros listed in the overview!
No, no... he was trying to charge me for the entire bottle of compressor oil, even though I only needed 50ml! (The rest is in the filling device and can be used for the next car! That would have been 46.15 euros just for the compressor oil!)

Either I get the rest of the oil, or he needs to calculate it properly!
So, he briefly prepared the items for sale, and then he was able to present a total amount of 51.34 euros on his computer! That was fine!
(However, due to a system error, the invoice will be sent to me later, and he couldn't print it out...)

Well, on the way home, I obviously wanted to test the air conditioning at full blast, but the air just wouldn't get cold.
Every 8 seconds, the compressor briefly activates for about half a second, and the engine speed decreases. At idle, it drops by about 50 RPM, and at 1300 RPM, it drops to approximately 1200 RPM.

The Climatronic's fault memory contained error code 119 (vehicle speed).
Deleted and then waited for it to get cold.

Unfortunately, that's not possible.

Could it be related to the fact that my WSS and combination instrument have a minor defect? The outside temperature was frozen at 13.5°C, and that sensor is also faulty...

So:
-Is it normal for the compressor to only run for such a short time?
- Is the refrigerant charge of approximately 0.8 kg okay?

-Is the refrigerant charge of approximately 0.8 kg okay?

800g should be fine - most cars are around that weight.

Most of the time, there's a sticker in the engine compartment indicating the correct amount of fluid to use. Often, it's also listed in the owner's manual.

Unfortunately, I can no longer rely on stickers or similar things because I also installed a different capacitor, etc., with the other motor.

Okay, that already reassures me about the quantity.

But is this constant, brief running now normal given the circumstances?

The brief start and then immediate shut-off in one of my older cars was caused by a lack of refrigerant in the system. Subsequently, or perhaps even before that, the compressor failed.

Hmm... What a piece of crap! / This is so frustrating! / What the hell!

Today's outdoor temperature was 23.5 degrees, and it's still doing the same thing.

What is the most cost-effective solution for testing this?

Okay, as far as I remember, the Golf 4 uses 850g of refrigerant R134a, including 150g of silicone oil.

I'm sure the issue has nothing to do with the WFS.

The compressor engages, and the resulting pressure is either too high or too low. If your compressor is working correctly, then the only things that could be causing the problem are the two pressure switches, which you should try replacing. They're not excessively expensive, and you can easily replace them yourself.

Here's what else comes to mind... A friend of mine retrofitted the Climatronic system to his Golf 4, following VW's instructions exactly. The climate control behaved similarly to yours, and the solution was that there was an error in the wiring diagram, and a pressure sensor was connected incorrectly. There was no error code either. You retrofitted the 150hp PD engine, so maybe something went wrong during that process, or perhaps you also encountered the wiring diagram error.

You should perform a pressure measurement; approximately 15 bar should be present on the high-pressure side, and approximately 5 bar on the low-pressure side.

Thank you, Julian!

That might actually be the reason!

I'll take a look at the pressure switches right away and see what I can do.
I had already received the 'pressure switch' error message several times when the AC system wasn't yet filled with refrigerant. But I thought that was normal and meant there was too little pressure because there was nothing in the system yet...