Skoda Octavia 1, 1.9 TDI: Poor AC Performance Due to Radiator Fans Failure

Hello, after a week of searching for the cause of the fault, I decided to write ...

Short info:
- Patient - Skoda Octavia 1, 1.9 TDI (90km AGR), manual air conditioning
- faulty fans (and / or) air conditioning compressor.

Some time ago I started to wonder why on very hot days the air conditioning in my Skoda works very poorly (manual air conditioning). After some time (further in the heat) periodically started to turn off the air conditioning compressor. After getting interested in the subject, it turned out that:
- fans on the radiator do not turn on (both smaller 300mm and larger 345mm),
- After switching on the air conditioning, the compressor starts, the system increases the pressure and at some point the compressor is switched off for safety reasons (too much pressure in the system).

The culprit appeared to be a burnt radiator fan (345mm). After disassembling and opening the engine, it turned out that there is nothing to do for the repair, because the plate with brushes and (probably) the coils is charred. Well, I bought a new fan (replacement), mounted, connected and everything started working. (maybe except for the fact that at the beginning I did not tighten the 14-pin plug in the fan controller to the end ) After switching on the air conditioning, the compressor is turned on and both fans started in first gear.

Everything worked for ... two days. The air conditioning compressor and fans stopped working.

Well, hop into the engine compartment, and the fork knife plug has loosened. I unbuttoned the plugin with the controller, I stretched back and then nothing. I look into the fuses and locate the culprit - 40 Ampere (Power cooling fans on the radiator) fuse in the box on the battery burned out. Happy I changed the fuse. (with the idea: If one fan has stood in place, a current would have to flow through the fuse temporarily, so it would distort it, but in turn it could just make a life after replacing the fan)

After replacing the fuse, unfortunately, no reaction - neither the compressor nor the fans. I dismantled my fan controller (number 1J0919506K) and everything seems to be working properly (no overburning, burnt elements etc.). I checked the relays: both react to power on the coils and close the circuits. I was not able to check the driver more because I was not able to find the control pins. In any case, closing the circuit in one of the relays (by manual method - by shorting the plate in the relay) causes the fans to start in first gear.

In spite of everything I bought another driver (a replacement with the same number and number of pins) and after connecting, it switches on the air conditioning compressor, but the fans will not move any more.

Has anyone already encountered such a problem?

Greetings,
Viktor

Hmm, and gas a lot?

Yes, the factor is. The air conditioning worked without any problems during these two days. Tomorrow I will try to connect the laptop with VAG and see what the car has to say

You have nothing to say because the manual air conditioning system is not diagnosable.
See if you have a 4-pin plug plus on pins 1 and 3.
See if there is a plus on the 14 pin plug on pins 4 and plus after ignition on pin 9.
The weight is 6 pin.
Power and mass check with a bulb of at least 21W.
I am surprised by your statement - a replacement with the same number and number of pins.
Like the same number, what is it about the replacement?
Is this module new?
Maybe you bought a broken one if it's a stimulant.
Here, there is no option for the controller to turn on the compressor during normal operation and not turn on the fans.
Did you have relay contacts with your finger then you had both fans running - slow and fast?

grala1 wrote:

You have nothing to say because the manual air conditioning system is not diagnosable.
See if you have a 4-pin plug plus on pins 1 and 3.
See if there is a plus on the 14 pin plug on pins 4 and plus after ignition on pin 9.
The weight is 6 pin.
Power and mass check with a bulb of at least 21W.
I am surprised by your statement - a replacement with the same number and number of pins.
Like the same number, what is it about the replacement?
Is this module new?
Maybe you bought a broken one if it's a stimulant.
Here, there is no option for the controller to turn on the compressor during normal operation and not turn on the fans.
Did you have relay contacts with your finger then you had both fans running - slow and fast?

Hello, thanks for the answer.
In the 4-pin plug I have a plus on the mentioned pins 1 and 3 (checked both with the meter and 12V21W bulb. 14 pin plug exactly as you said: "fixed" plus on the pin with the number 4 plus plus after ignition on pin 9. Pin weight 6 present.

Regarding the replacement, one photo will explain more than 1000 words so:

On the right you can see the housing of the driver, which sat by default in the car, on the left a new one purchased recently. Maybe I have wrong thinking when it comes to nomenclature - for me the original would be a part with embossed the AUDI, VW or Skoda logo. Here I have some other company - so for me it is a replacement. If I mislead you, I apologize

In any case, going back to the fan gear in the 4-pin driver plug:
I understand that pins 1 and 4 (thicker connectors) are responsible for the second course of the fans, while pins 2 and 3 only start the first gear?
In my case only the short circuit of the relay on pins 1 and 4 gave the result in the form of fans switching on with the speed as in the following movie -
I therefore conclude that this is only the second course.
[movie: 720p, ~~ 30MB]
[Film: d751440268] https://filmy.elektroda.pl/88_1505565263.mp4 [/ film: d751440268]

I am left to look for problems in the fans themselves. In a moment, I will check whether the new controller includes any of the relays.

Now two questions:
1. In what order does the air-conditioning and associated fans start? After pressing the button in the cockpit, the relay responsible for the first course of fans and then the air conditioning compressor is started. Actually, what is responsible for starting the air conditioning compressor? Is there an extra relay somewhere?
2. I was not able to see in a disassembled fan - on what principle is the first and second gear being implemented? At the first gear, the fans are connected in series and the second in parallel? I would gladly test the fans for a short time, but I was not able to find information on how the gears were made.


Best wishes,
Viktor

-------------------------------------------------- ------------------------------------------
Well, I'm after further measurements. The old controller does not turn on the air conditioning compressor or short-circuits.

The new controller switches on the compressor and closes the contacts from the first fan speed.

A NEW fan is probably burnedfirst gear (no voltage between ground and positive first gear when fan is spinning). stretcher xxxxx

Moderated By T5:

I censored the word

. After a few days?! In addition, he probably killed the old driver. Now I wonder how to complain. I assembled the goods myself, I have receipts, but in total I am over PLN 200 back ...

You have three 30A fuses on the battery. which supply power to three red wires right after these fuses, check if there is power on these wires, of course the fuses and the power supply on them also check.

It is the fan controller that activates the compressor and the first fan speed, it does it simultaneously.
The fans are connected in parallel so you can connect each one to the battery or rectifier in the form of a test.
You can also for the test and it is probably the simplest solution to unplug the 4-pin plug from the fan controller.
You are bridging the red and black wire from pin 1 with a red and black wire from the pin 4 - the second gear should start on both fans.
You are bridging the red and black wire from pin 1 with a red and white wire from pin 2 - the first gear should start on both fans.
If you do not start the first gear on both fans, then how you want to save it you can add a resistor for each fan and you will have the first gear without replacing the fans.

milejow wrote:

You have three 30A fuses on the battery. which supply power to three red wires right after these fuses, check if there is power on these wires, of course the fuses and the power supply on them also check.

These fuses supply power to the fan module and, as he wrote earlier, he already checked the power on pins 1 and 3 of the 4-pin plug and 4 pins of the 14-pin plug - they are powered by fuses you mention (so exactly there should be two 30A fuses and one 110A - badge ).

Welcome,
So far everything works
After replacing the fan with a new one and attaching a new controller, everything works (ie after pressing the AC button (and the winding knob on more than 0), both fans in the first gear are switched on and the compressor = cold air from the vents). I have a few questions now:

1. Should it be the case that just pressing the AC button (blowing to 0) starts the first fan run, even without the engine running? When the engine is on (airflow at 0), the compressor does not start, the fans also start in first gear. I have not checked it before honestly.

2. I wonder if the source of my problems was not ... roll / mistake (as he called a bill) in the shop where I bought a fan. Why? I checked thoroughly that I need a fan with the designation 6X0959455 F (250W / 60W). At the moment, in a shop that I chose "finished" fans from one of the producers, so a delivery from another manufacturer was to come a few days later. After the phone asking for availability, I went to the store and bought a new fan. There was another indication on the carton (I do not remember exactly what was in front of the final mark.) In any case, the part number (most likely) on the carton was 6E0959455 AND the letter A was crossed out and it was written F. That is why I am beginning to have fears whether by chance they sold me a fan with lower power (100W / 60W), which damaged my driver. Unfortunately, I do not have pictures of the print on the carton, I have only fan pictures, which is clearly shorter than the original and the replacement I got now. Possibly, because of the lower power of the second gear damaged my first gear and driver? I wonder how to bite another complaint now - this time to damage the fan controller.
Below the photo of the fan.


Greetings!

Hi. If wrong section, please feel free to repost to the correct one.
Skoda Octavia 2 FL, 2.0 BMM. The fans are not working. After removing both and unplugging, when I applied power to the small one, it works, the big one does not. I found the big one damaged, ordered a new one and still the same. The large plug has plus and ground on the large pins and plus on one small pin. Interestingly, I started playing with the old one and after swapping the poles it works.... only that in the other direction (that's logical).
I connected the small one to the new one and tried the same and they work in the opposite direction. When the power supply is applied correctly, they both stand. Gentlemen, I know you have a wealth of knowledge and I am counting on your help. Regards.