Condenser fan test without any AC refrigerant

[SD1too]

Thanks very much Nathan for posting the result of your test which will be helpful to us all.

Originally Posted by Savestones

I was under the impression that turning the aircon off and demisting on should not require any aircon functioning ...

Pressing the windscreen demist button also turns on the air conditioning. This is because the demisiting efficiency is increased by using the dehumidifying effect of the air conditioning.

Simon

[Savestones]

Originally Posted by SD1too

Pressing the windscreen demist button also turns on the air conditioning. This is because the demisiting efficiency is increased by using the dehumidifying effect of the air conditioning.

This is also what the mechanic that filled up my aircon told me. I also figured it was a good thing to note for anyone performing the condenser fan test, as it has now saved me a few bucks!

[SD1too]

Today member Stocktake has posted that the "demist test" on his 1999 Rover 2.5 KV6 results in the radiator fan running when the air conditioning is completely discharged.

Originally Posted by Savestones

Here is the interesting thing: after filling up the aircon, the condensor fan was running again when doing the demister test!
Based on this, I concluded that the demist test for the front condenser fan only works if there is sufficient aircon coolant in the system!

In post no. 1 in this thread, Savestones found the opposite with his 2002 ZT 2.5 KV6: the fan didn't run when his air conditioning was discharged. It did run as soon as the air conditioning was recharged.

I think we're going to have to wait for more evidence before we can draw a conclusion on this question.

Simon

[suzublu]

Well my fan ran using the demist test when my Aircon was empty 🤔

Sent from my SM-A326B using Tapatalk

[Savestones]

Originally Posted by suzublu

Well my fan ran using the demist test when my Aircon was empty 🤔

Hahaha, this seems to complicate things. Could it depend on the specific type of engine?

[xsport]

hi Nathan. Glad to note that your aircon is now up and running.nice to hear. can i ask just for curiosity sake: when you did your original aircon test , was the car cold and with the engine running ? also if you can remember , did the heated rear screen light come on , along with the cabin heater blower , which should ramp up to maximum speed ? no worries if you cannot recall .. im just curios, ....

[SD1too]

Originally Posted by Savestones

Could it depend on the specific type of engine?

It's possible yes. Suzublu has a 1.8 litre with the MEMS rather than the Siemens engine management ECU. The two may be programmed differently as far as air conditioning condenser fan control is concerned.

Simon

[SD1too]

Originally Posted by xsport

... when you did your original aircon test , was the car cold and with the engine running ?

This is what Nathan says in his first post ...

Originally Posted by Savestones

With the engine on, AC off, and the demist function on my fan is not spinning at all.

He didn't say whether the engine was cold or hot but since his fan didn't run we can discount engine coolant temperature affecting the test.

Simon