C5 AC fan issue

[barbrady]

I checked my car with diag today, and found this fault. I tried to start the fan with the diag, but happened nothing. Started the engine and I watched the fan when I heard that the AC compressor switched on. Happened nothing. After I pushed a bit the fan blade with my finger and then it started. Has anybody idea what is the problem? Possible to repair or renew, or must change it?
2009 C5 2.0 hdi RHR

[GiveMeABreak]

It's possible the relay has gone - or there is water ingress into the wiring. Post up your VIN and I'll check the part
P0495: Cooling function fault inside ECU : Coherence

[barbrady]

I send it to you in pm.
That's true I went about 300 km in big rain today.

[GiveMeABreak]

Relay is 3, but I suspect water ingress to the connectors - try drying out the connectors / cleaning them with some electrical contact cleaner first BUT - I really wouldn't put your fingers anywhere near it until you have disconnected the battery - especially as you have been running it to temp - the fan can kick in automatically even with the engine off!

Also, if you are going to disconnect for cleaning - make sure you leave the car 15 minutes before disconnecting the battery to ensure the ECUs remember the parameters (also mentioned in the docs).

In case you need to replace it:
Fan (1): Part 1253 T3 (replacement part)
Relay (3): Part 9673028680

[barbrady]

How can I test the fan? Which wires I have to give 12V?

[wurlycorner]

If the fan started when you pushed it, it's quite possible the bearings are failing and have gone stiff and the motor just doesn't have the power to overcome them (your hand just giving it the push start it needs). I had this problem on my series 1 C5, but didn't realise until the bearings completely seized and the fan wouldn't run at all.

How easily does the fan spin when you try it wholly by hand (car off/no power to the fan)?

Does it still come on/off correctly with engine temperature? (leave the car running stood still, let it get hot with thermostat open and see if the fan comes on or the temp gauge continues to rise). Alternatively check the feed to the fan with a multi meter.
Not seen the wiring diagram for that car, but looking at the parts images I would fully expect that the wires on the two-pin plug are the +12v / 0v, so when the fan is meant to be on, you could just put a multi meter across those and see if you have a feed. (I suspect the single pin plug is just a sensor that determines if the fan is running or not???)

[xf1ref]

Maybe the carbon brushes are worn and do not make contact with the collector...or if you have luck is just water and you have to let it dry. I think that the electric motor is encapsulated and is somehow more complicated changing the brushes.

[barbrady]

I removed the fan and measured the resistance between the two big plug. The result is 80 Kohm. So it seems the fan motor is over. Probably the brushes.

[barbrady]

Did anyone replace carbon brushes in this kind of motor? Possible?

[Bandit12]

Hi, I had similar issues on my mk1. Brushes had worn out and relay faulty. Tried replacing brushes with donor ones but opening the motor can was very difficult and time consuming. I gave up n bought replacement fan from local motor factors for 70 quid and got replacement relays off ebay for about 8 quid. Worked perfectly after that.
Bandit

[Stickyfinger]

Similar on my X7, had to replace it with a new (OEM) from Poland, about 2/3rds of the Uk price with good service.