Hi folks,
I have a 2006 ML320 CDi W164, right hand drive (UK). I have a problem with my radiator fan coming on about 5 seconds after start up and remaining on until switching off the engine. On checking with my iCarsoft I am getting the following, B12 open circuit. Where do i locate the B12 Refrigerant pressure sensor and can it be repaired DIY or is it a mechanic job?
Thanks in advance for any support


B12 sensor

 

 

Sorted!!! Cable connector off...cleaned and firmly fastened back on, DTC cleared, main fan no longer coming on.....hoorah!

 

Thank you so much.

 

Hi Major,
I have problem with my ML500 air con fan blowing warmer air at random while driving. It gets better when idling; otherwise decent cool air is blown. Would replacing this sensor rectify the issue?
Thanks,

 

Did you ever consider checking for codes?

 

Yes. With a scanner equipped with Mercedes software that checks for AC as a feature. Got all clear message.
My guess is perhaps one of the sensors is on the way out. Besides, the cool air is not really a chilling cold air as it used to be, but it's ok.

 

Then I would say that your refrigerant is not up to par caused by a slow leak somewhere in the system.

 

If by not up to par, you mean of low pressure, I keep checking the refrigerant pressure. The pressure has been dead on every time I check with a gauge. Not a slightest drop.
Would this intermittent cold/warm air not the result of a sensor going bad?

 

Spend $70 and get a real scanner.

 

Finally got 3 codes using a new scanner, namely 9601, 9803, & 9804, as per attached. Do these mean I have to pull out the dashboard?
Thanks

 

You get to play again...

stored faults... zero current fault 👍

If i had to guess, I'd say someone played with all the buttons too long. Now you know this car is watching your every move

Clear these codes then scan again after couple drive cycles.

 

Yes, because of the issue I had, I did play around with the buttons. I did clear the codes and now I have no codes after a couple of cycles. But the original issue still exist.
I'll keep an eye and report back. Thanks

 

ok, now you know there is nothing your AAC Module is complaining about: no fault!

It's up to you to analyze the data it is using....

• pressure data
• temperatures data
• ....

Q: Does your A/C compressor uses a clutch or always spins non-stop ?

 

Always on

 

these type of compressors are activated by a solenoid that gets lazy... bang it, test it or replace it
👍

 

Great, thanks a lot. Would you please share the part number for the solenoid. Thanks.

 

I would if I had it. Find this item attached to the compressor body.

 

Thanks