Condenser Fan Unit

[Bimmer_Me_Up]

A few weeks ago the radiator expansion tank cracked and started leaking coolant. I replaced it and went ahead and changed the thermostat and hoses as well (125,000 miles). Afterward, I noticed that when my X5 is moving, the a/c cools fine, but when I stop at a light, it starts to blow warm air. I did some research and found that it could be the Condenser Fan Unit, behind the radiator (not to be confused with the auxiliary fan in front of the radiator). Has anyone here had this problem and had this unit replaced? If so, what is the part #?

Also, where can I get it? I checked Bavarian Autosports and ECS Tuning, but they don't seem to carry it. I haven't checked with the stealership yet. Thanks.

[white lancer]

The fan behind the radiator with the viscous clutch is nothing to do with the air conditioning system. It is a mechanical fan for cooling the radiator only.

The aux fan in front of the condenser is for the air conditioning system. This cools the condenser. Your air con won't work unless the aux fan is working correctly.

The aux fan has 3 cables going to it. +12v, ground and a square wave pulse signal which controls the speed of the fan from 10% to 90%

It sounds like when you are moving the condenser is being cooled enough to make your air con function, but when you are stopped your condenser is not cooling correctly so the air con is blowing warm air

[Bimmer_Me_Up]

<<It sounds like when you are moving the condenser is being cooled enough to make your air con function, but when you are stopped your condenser is not cooling correctly so the air con is blowing warm air.>>

Thanks, that is exactly what is happening. Though, I am bit confused now. I took it to a mechanic and he said that the fan with the viscous clutch behind the radiator is failing and is causing the AC to not work properly, but your suggesting that it is the other way around. If that's the case, then that is a somewhat easy fix. Have you dealt with this same issue?

[Bimmer_Me_Up]

Nevermind, just talked to Bavarian Autosports, they said it could also be the resistor on the Aux Fan, very common problem. I think the mechanic is wrong. Thanks for your help.

[bcredliner]

There are usually other symptoms associated with a bad aux fan resister such as fan seems to haunted, changes speeds always on high, etc.

Have you checked to see if the air conditioning is fully charged?

[white lancer]

Originally Posted by Bimmer_Me_Up

Nevermind, just talked to Bavarian Autosports, they said it could also be the resistor on the Aux Fan, very common problem. I think the mechanic is wrong. Thanks for your help.

There is no resistor on the aux fan?

I think they are talking about the final stage resistor on the heater blower which is inside the car and nothing to do with either problem?

To answer your earlier question, yes I have a similar problem. My radiator fan viscous clutch was bad so i changed it out a few weeks ago. very simple job which took about 20 minutes.

I actually think you have two issues. The first being your viscous clutch is bad and the second being your aux fan is bad. The reason i think this is because your radiator fan is turning albeit not as fast as it should be and when you are moving you also have air flow through the condensor / radiator etc to cool it, hence your A/C works when driving along. when you stop the aux fan is not cutting in to cool the condensor and the radiator viscous clutch is running but this is not powerfull enough to draw fresh air through the condensor radiator, hence your A/C blows warm air until you start driving again......