Check the coolant and oil temperatures with VCDS after you've parked the car, and then when it has cooled off, to see whether the temperature sensors are not reporting some wrong value. Of course also look for any fault codes.

 

Didn't he say blower fan? Did you read Rad Fan?
Not sure that overheating would trigger the interior fan to cycle..... that doesn't remove that much heat from the system!

 

Blower fan staying on is a new problem for us.

My best guess is the bitron and that would be the part I would test first. See post #8 for pictures.

www.clubtouareg.com/forums/f43/ac-heater-blower-motor-21543.html

 

thanks, I will test the bitron, as the tech at the stealer is pretty much just guessing, so far. Wants to change out the heater/ac control panel for over $800 and the sensors under the dash for 3 hours labor plus there is always the "shop supplies" Always "shop supplies"

 

Same thing here. Went out to start T-reg and battery was dead. Once I jumped it off, the fan will not stop blowing even with fan control set to off...until the battery dies again. Is there a quick fix? Blower fan fuse is where I'm gonna start.

 

If you find out what is causing this, let me know asap. This really sucks, I am pulling fuse whenever i stop the car, for now. Can hardly justify spending that much on a repair to the heater and it seems they are only guessing at the repair right now

 

So, I tried your trick, pulling out the 40A fuse on the driver's side at the top of the fuse panel, cuts power to the AC/blower fan. I charged up the battery and got the VW running.

I then plugged in my Ross-tech VCDS and cleared out all the fault codes because my battery had run dead and set off a ton of irrelevant low voltage fault codes. I restarted the VW and then checked for fault codes again and found the following:

Address 08: Auto HVAC Labels: 7L6-907-040.clb
Control Module Part Number: 7L6 907 040 AD
Component and/or Version: CLIMAtronic R/L 4326
Software Coding: 0020030
Work Shop Code: WSC 31414 790 00001
VCID: 72EA5DDD696F4ADAD3-8026
1 Fault Found:

00353 - Function Return Message from Fresh Air Blower Regulator
001 - Upper Limit Exceeded
Freeze Frame:
Voltage: 13.50 V
Voltage: 6.05 V
Voltage: 11.77 V
Voltage: 14.00 V


I found SSP301 The Touareg heating/air-conditioning system
http://www.volkspage.net/technik/ssp/ssp/SSP_301.PDF

I have the 2C-Climatronic system.

My thought was that the Sender for blower control, front G462 (Bitron) may be going bad but, page 73 in SSP301 states:

Function:
"The sender for blower control is activated by the Climatronic control unit using a pulse width modulated signal (PWM). Power is supplied to the control by the Climatronic control unit J255. According to its demands, the sender regulates the blower motor in the air-conditioning unit."

Effect of drop-out:
"If a blower is defective, the entire heating and cooling function of the air-conditioning system fails. The diagnostics can be used only indirectly to localize a fault on the blower control unit or on the blower. For this purpose, there is a resistor in the blower control unit; this is connected with the minus pole of the blower motor. Due to this arrangement, the control unit receives ”acknowledgement information”, which can be used to determine whether the fault is at the sender, at the blower or both. There is no direct indication for a fault on the control or on the blower. However, the voltage signal of the resistor in the blower control is not a signal for the actual voltage on the blower motor, but rather a signal with which the Climatronic control unit can ”observe” the behavior of the sender for the blower control."

So, that being said, I don't know if the fan running all the time necessarily means that the G462 is bad, but power is still somehow getting to the blower fan even when the ignition is off. I know there is a feature on the car which allows the fan to run when the car is off, it is the Residual Heat Function (REST) but it usually operates at a reduced blower fan speed to prevent the battery from running down too much so I don't think that is the problem.

Back in the summer my fan quit working for a few weeks and it has been making sounds for the past year or so. I also noticed, during this latest vehicle startup, a slight hot electrical wire smell after the VW had been running a few minutes. I think my fan motor is at the end of its life and I am going to start by replacing it Part#7L0-820-021-Q (right hand drive). If that doesn't do it I'll replace the G462 (Bitron) Part#7L0-907-521-B

 

You are overthinking the problem. Look inside the bitron.

I have a problem. The blower runs all the time and you can not change the speed at a constant speed. It can not be turned off even after removing the key from the ignition. I noticed that if I turn it to OFF, the engine will slightly throttle as short as it would (but the fuses did not blow).

VCDS error

00353 - Function Return Message from Fresh Air Blower Controller
001 - Upper Limit Exceeded
Freeze Frame:
Voltage: 14.10 V
Voltage: 5.89 V
Voltage: 10.48 Volt
Voltage: 14.00 V

I dug a bit and it turned out that the contacts on the resistor pole were damaged. Probably from old age and temperature. They burned up and melted the socket in the resistor housing and plug. The old Bitron is trash.

Still, replacing the fan motor is a good idea. You can replace the fan motor now or replace it later, but you will eventually replace it. The fan motor is a wear item in this vehicle.

 

Yes, looking at the schematic, looks exactly like bitron, G462 is sending the ground to the heater motor, so might have gone bad, and that explains why motor runs with key off and removed. This is the only place the motor would receive power, the positive side is connected always and the ground is switched on or off from a signal the bitron is receiving from the control unit, or in this case even not getting a signal, it is still grounded because???the bitron is shorted out??

 

The Bitron sounds like the culprit to me then. Bitron replacement first, fan second. Does anybody know what the voltages should be?

 

It looks like the large spade lugs (which modulate the power to the fan) inside the bitron shorted. It will be interesting to see if the same thing happened to both of you. If you replace the bitron and fix the problem, please check the old bitron and let us know.

.

 

Please tell me the Bitron is not a VW factory code item..

 

Bitron was the culprit for me, fan seems to be fine for now. Does anyone have any suggestions for replacing the plug on the wiring harness? My wires are melted too.

 

Bitron was the culprit for me. My end connector on the wiring harness melted too, does anyone know where to get a replacement clip?

 

Jip. Just had the same.

New bitron on the way. I also requested a piece of the harnass from the breaker.

 

4ePikanini, Do you have a part number for that piece of wiring harness? Who did you order from?

 

There is a cutaway at the back of the cubby hole. Very easy access to it.

Just prod around with your nail, you will find the perforation lines.

 

After taking some clearer photos of the connector, I found the part number 1J0972752. I think I have lots of options now. I'm going to strip the insulation back and see how far that corrosion goes.

 

Thanks to the part number, there are all sorts of options. Good work guys.

www.google.com/search?q=1J0972752

 

My part arrived yesterday, from a supplier called GermanOEM in Ontario, Canada. Much cheaper than the stealership and exactly same part, go figure!!! Took all of 15 minutes to replace the bitron and now....VOILA....heater works fine. I was quoted almost $2000 to supply and replace the (probably) wrong part and it only really cost $200 including shipping. Now I am going after the VW stealership for my money back from the estimate for repair, which was $188.

 

My part arrived yesterday, from a supplier called GermanOEM in Ontario, Canada. Much cheaper than the stealership and exactly same part,

They are one of the best places to get parts around our neck of the woods.

 

Finally got everything fixed. I ordered an OEM Bitron and plastic connector. I couldn't find a wiring pigtail that I was comfortable buying so instead I broke off the old on and trimmed back the melted wiring insulation. I then installed heat shrink over the exposed wiring and slipped the original wiring ends into the new connector and then buttoned it all back up. It works like a charm! Thanks all for the help!

 

Silly question but I have the same problem, I have ordered the Bitron but I'm having trouble getting the old one out, I csnt quite get to the top screw did you have to take the glove box out.

 

I just developed the same issue on 2004 V6. I have had a defective blower that shimmies at times. So just now, it would not stop with the car turned off and locked, alarmed. So I used advice above and pulled the 40A fuse on driver's side. That at least got me closed down for the night. I had my egg in the shop a few weeks ago for a bunch of stuff. They told me my 2004 is getting to the money pit point. I was hoping these issues would hold off until I could trade it in. If it keeps up this crap, I may have to park it in the back yard. and just drive it when there's ice and I don't mind if someone totals it.

 

Total the vehicle. Humph! I put in a $30 generic fan speed controller (bitron) from ebay in. It's been working perfectly.

 

Hello,

I konow this discussion is an old one, but it has my issue. I have to replace the Bitron (interor blower resistor) as the blower is continually blowing even when turned off. I've read all the posts above and it seems my issue might be the Blower Resistor. I can see it... blue, screwed in right up behind the glove box.

My question...... how have you all removed it? Looks like I have to take the glove box out, which entails unscrewing the cente console as well, pulling the radio, just to get to the single screw on the left hand side?

Surely there's an easier way? I can see a marked panel at the back of the glove box that if I cat through I can get to the resistor.

Regards

Adrian

 

My 2011 Multivan T5 had the problem of the front cabin fan running even when the ignition was turned off and key removed.

I fixed it by purchasing and installing this blower motor controller.

Search for Ebay item: 402403591938

Type: Blower Motor Resistor
Material:Aluminum & Plastic
Manufacturer Part Number: 7L0907521B, 7L0907521A, 7L0907521
Reference OE/OEM Number: 7L0907521, QRES7396, YL7396, 7L0907521B,7L0907521A,7L0907521
Size:11.5*3.7*8 cm
Features:
1.100% brand new, never mounted, premium quality
2.Stable performance, high reliability
3.Durable and practical product
4.Perfect aftermarket replacement,easy installation
Fitment:
For Audi Q7 2006-2017
For Seat Alhambra 2010-2017
For VW Amarok 2011-2017
For VW Multivan 2003-2015
For VW Touareg 2002-2010
For VW Transporter 2003-2015
For VW Transporter/Caravelle 2003-2015
For Porsche Cayenne 2003-2010

 

Ok what is the bitron exactly? Are we calling the resistor the bitron?

 

The resistor pack for the fan on the T1/T2 is also referred to as the Bitron and is separate from the blower motor.
On the T3 and up it's all in one but some have had success in pulling apart the blower ass'y and replacing the resistor pack.

 

Ok thanks, I have the old 2004 Touareg so I’ll look it up but it must be a T1