fans always on

[BrettM]

The cooling fans on my 06 BRM come on with the ignition switch, not just when the engine is running. A/C has been inop since I bought the car in 2018. Replaced the engine earlier this year and about 1000 miles after engine r&r, the fans started staying on 100% of the time until 15-30 seconds after the ignition is turned off. Any help with this fix is appreciated.

 

[metallica21156]

Probably need to replace the fans. Module likely died.

 

[sinneD]

I'm wrestling with the same issue.

Throwing a $400 fan in there is not the same as a $20 sensor.

Are you able to scan the vehicle for codes? Do you have access to VCDS to read sensors / measuring blocks?

My 06 also has inop A/C and I think that it may be related.

 

[Vince Waldon]

A defective Fuse #16 has been known to cause these symptoms, strange as it sounds.

 

[Seatman]

On my car the coolant temp sensor seems to play a part in the fans even though I also have a thermostatic switch at the bottom of the lower hose. Not sure how it's connected but it seems to have an influence on the control module.

Different car but it is a 2007 2l PD vag based car.

 

[TurboABA]

Typically. when the coolant sensor on the rad outlet fails in most systems, the ECU will kick the fans on at full bore as it no longer can tell if you're running hot or not.... kinda like a safe mode. If you're just throwing parts at it, I'd start with that sensor first. Otherwise, take readings and\or log them with VCDS to confirm.

 

[TurboABA]

On your BRM, it should be the sensor right by your oil filter housing, on the tstat pipe on the front of the block (G83).

 

[sinneD]

Ok, so the 2 coolant sensors ARE on different measuring blocks. I was reading G62 which is the one I believe on the manifold under the tandem pump.

I am not a 'throw parts at it' kind of guy usually. Here is the results of VCDS scan after clearing the codes b/c of dead battery: VCDS Scan on Pastebin

I verified that I have freon in the system (50psig). Refrigerant pressure lower limit seems suspect.

What I am struggling with is the Aux Heater and Rain Sensor code too. I pulled Aux Heater and reflowed the components per the writeups and that had no effect. I am starting to wonder if a controller is or module is going bad or another wiring fault.
Nav fault code has always been there.

Are there point-to-point tests somewhere? I am so disappointed in Bentley- I thought there were on the CD manual which, yeah, whatever. Then the eBahn subscrition expired. I thought they were on there. So I broke down and bought the paper copy. nada, zip nothing.

I want to at lease Ohm out the sensors and see if they are bad or not.

Any other thoughts or tips?

sinneD

 

[TurboABA]

Wait....What? I thought this post was about fans being on?

 

[BrettM]

Thanks for the replies everyone! I do not have access to a VCDS and the nearest dealership is 90+ minutes away. I finally replaced the temp sensor next to the thermostat and it did not correct the problem. I'm wondering if a bad wiring harness could cause the issue as well so I'll be probing a few places with the multimeter. Also, since my wife also drives a TDI, I thinking it's time to invest in the VCDS.