We're talking about 2 different things... The AUX fan I was referring to is the electric fan in front of the radiator/condensor. There is no electric activation of the engine fan that is connected by the waterpump shaft. The clutch on that is thermostatically ativated by heat alone, and is designed to be released when not needed to reduce strain on the engine.

The clutch status you were seeing in status request was the compressor clutch, not fan clutch. In the control module functions you could click test modules or component activation (whatever it is called in the GT1 version you are using) and select auxillery fan or electric fan, whatever they call it in that version, and activate it. It usually gives you choises of 30%, 60% or 90% activation. I'd test all 3 output stages.

Weasel, thanks as always for replying !
I'm not that bad! But I wasn't clear enough. I meant AC Compressor clutch. GT1 shows it's ON shortly after button on panel pressed but clutch is not engaging. I have pretty good knowledge of AC systems. It's not cycling, nothing! AUX fan in front of radiator doesn't come on either.

I only hear DME adjusting RPM's for expected load from compressor, thats it.

Bentley says aux fan should come in when car started for short time, that doesn't happen.

Are they interconnected? Auyx Fan and AC compressor clutch?

Does your system have the proper refridgerant charge? Did you check the fuses? It looks like the system is trying to activate the clutch but something is stopping it whether it be the power not getting to it or something else. There is only one wire to the compressor, and it is right on top of it... So that would make the signal to the clutch easy to read with a meter.

And the AUX fan is activated by the DME and affected by different inputs to the DME, the AC clutch is the same. The IHKA (ac control) makes the ac request and the DME has to release it depending on what it sees with the different sensors etc.

I will check tonight. Fuses is OK. I would think that if it was low on freon then it would cycle. No? ALso, failure pattern was different. It was working perfectly one day and just stopped.


Can it be checked with GT1? Like I said, it says that Button "ON" and shortly after says clutch "ON"

Thanks for the reply...I have actually fix the problem.

1st thing I had to do was to replace the AUX fan.
2nd Took it to a shop which checked for freon level

Still no ac; but they did check power to the compressor and found there was power but the clutch was still not turning on..

I actually removed the clutch without disconnecting the compressor lines and found there is a fuse (1A 250V) that had gone bad. This seem odd I had never seen a fuse on a AC clutch before. Tried to find the fuse; but did ot. So, I bypassed the fuse with a thin wire. All is good now! the compressor is working and the AC is ice cold.

Would have cost at Min. $500-$600 to replace compressor or as much as $1000-$1500.

Yes the aux fan can be checked with the GT1, as can the ac clutch activation. When you go into the DME control module in "expert mode" there will be a spot called component activation that will pull up a list. In that list will be electric fan or aux fan, whatever they call it in that menu. The ac clutch activation would be in the ac control module (IHKA).

Do you mind giving more details on how I do that?

It's very nice have a tech on board to handle the difficult questions. Great job, Weasel!

What year is your X? (the user interface is different on some than others)

Try the control module functions button on the right bottom of the page after the short test is done. In there select DME from the list, then see if there is a link in the middle window for component activation. If so then it is in there. Otherwise you gotta go through function selection, complete vehicle, DME, test plan. Then go in through there to expert mode then component activation.

It's 2003 3.0 5sp
I will try that tonight. My DIS v55 if that makes difference, I beleive there is no programming in there, but activations should be. Right?