C5 X7 heater blower motor resistor location

[GiveMeABreak]

Are you sure you have a) the correct part number for the X7 and b) a decent branded part - anything from Eurocarparts will likely be dead on arrival, faulty or won't last 2 minutes.

Just to give you a comparison, a genuine Citroen OEM part will set you back £160 as of today - so I wouldn't expect much from the numerous cheaper £16 Chinese ones on the market. There is of course everything in between those prices

[coarist]

Thanks Marc. The one resistor that I replaced was the "cheap"-er ones.

I brought a second hand heater control panel and tried it this afternoon. There is no change, neither improvement nor does it getting worse than it was before. There is no fan speed control.

Due to season getting warmer, I tried turning on the air-con. I opened the bonnet and observed the air-con pump clutch not coupling.

I will try obtaining a genuine Citroen blower motor speed control module and try it.

------ 01 May 2021

Checked all fuses for extra peace of mind. Connected Diagbox to OBDII to obtain a better picture of the situation. With the new but speed un-adjustable "cheap"-ish fan regulator module installed:

Code: Select all

CLIM : Air conditioning 
Response data 
      R61809665262380001996652623801A0CFFFF014060190599 
State of the ECU: CLIM_REGULEE 
Reference 1 : 9665262380 Reference 2 : 
Faults present : 4 
      F72F : air blower fault 
      Characterisation : not characterised 
      Status : 
      Location : local 
      Variables associated with the fault 

Brought MAHLE BEHR replacement part, named "AC blower regulator". Full fan control is restored just by replacing this part.

The part is marked "CITROEN C4", and it worked on C5 X7 as well.

MAHLE BEHR
P/N ABR 21 000P
5DS 351 320-011
AC blower regulator
CITROEN C4 (also work on a C5 X7)
Made in Germany

The faulty part has been further diagnosed. Encased inside the module, the MOSFET power transistor has all three terminals S D G (source gate drain) short circuited. This failure mode corresponds well with full blower motor blast fault that I experienced.

Faulty blower regulator does not occur frequently but it is not uncommon. I had replaced blower regulator on Mercedes S320, Peugeot 406 (but this car is not mine, I just helped fixing it) and on Citroen C5 X7 (this occassion).

Probable causes: normal lifespan of the semiconductor device / voltage surge or spike above tolerated level.

[GiveMeABreak]

Ok, so possible multiple issues - so you need to check further

Clutch not engaging on compressor can be low gas (acts as a safety cut out). But this won't affect the internal blower in the car:-
The Blower Motor Control modules are known to not work with cheap Chinese copies - get a decent one if you suspect it is the Blower Motor Control Module.

[coarist]

Resolved.
Repair is successful.

[GiveMeABreak]

Thanks for the update - did you end up having to replace the first new module with another new one?

[coarist]

Yes, that is correct. The first one that is "cheap"-ish does not function as intended. Reading forum posts and on Marc's accurate suggestion, I purchased a second branded one. That sorted the problem making me a happy person.

Air-con is working as usual after this. It was a false alarm when I thought earlier that it did not work.

[GiveMeABreak]

Great - thanks for the clarification - it helps others in the same boat realise that this is a major issue when choosing parts.

[gustav]

Old thread but would like to agree with what you say about the shortcomings of aftermarket products.

My cabin fan was only running on one speed on a 2014 c5 Crossover I recently bought. I took a 15 year old resistor from my old 2010 c5 x7 which fixed the problem right away. The old resistor was an oem Behr but on my new car someone had installed an unbranded aftermarket part.