A/C Delayed Cooling

[2003x5guy]

Hi Guys,
Summer is here and the air is hot!

A/C is on the fritz....sometimes...

Turn car on, blower fan blasts the air out of the vents like normal. Only issue is its NOT COOL air. Start driving around and about 5 mins later (sometimes more, sometimes less), I hear a soft squeal as if the pressure is building and then the air starts coming out of the vents ice cold, just as normal.

I have done some reading but I can't say I have found the perfect answer to this yet.

The auxiliary fan does spin and the compressor appears to be running fine.

Things I noticed:
1.air only seems to start cooling when the Aux fan is spinning. Pushing the outside air through the coil.
2.when the air is NOT cooling, I don't hear the compressor clutch going on and off like normal
3. I already checked the R-134a pressure. Its fine.

SO

Is the compressor fine just waiting for the instructions to engage?
Is the Aux Fan switch bad? Going Bad?
Anything else to check?

Seems like its going to be a simple problem since the air does cool just fine when working right.

Thanks.

[cn90]

The Clutch may be slipping but this is a variable displacement compressor, the clutch should be on all the time (when the AC button is pressed).

Could be bad HVAC panel sending out signal later than should be.
Perhaps you can remove the HVAC and give it a good clean with compressed air.

[2003x5guy]

Well, lets say I'm pretty positive I remember "seeing and hearing" compressor clutch engage and disengage last time I was under the car, but I could be wrong.

At the moment I'm focusing on the part 13621433077 Aux fan switch as the problem.

[cn90]

PN 13621433077 is not fan switch, it is coolant temps sensor.
This part tells the Aux Fan when to runs high speed.

When this part goes bad (shorting out), the Aux fan runs all the time.
Not likely to be the problem in your case but I may be wrong.

[2003x5guy]

Well, maybe that's the problem. It will run high speed but not low speed? Faulty sensor?

[cn90]

It will run high-speed draining the battery.
But you will get cold air regardless.

[2003x5guy]

Ok, any other ideas then? A/C Pressure switch?

64539181464

[upallnight]

You should check the low side pressure when the clutch disengage. The low side pressure may be so low that the low side pressure switch is disengaging the compressor and will wait for the pressure to build up before engaging the clutch again.

[g300d]

Sounds like what happened to me. Turns out it was the compressor.

delayed AC

[2003x5guy]

How does/did the compressor fail? I did some research on the variable non clutch compressors which are supposed to be in BMW's. It seems pretty robust.