IC fan cycling with a/c compressor?

[N2BUICK]

Adding R12 to the system this morning, noticed the IC fan is cycling off when the low pressure control stops the compressor off. Fan cycles back on with compressor.
This might have been this way for a long time. I have unplugged the 3 terminal connection at the fan delay relay, a long time ago. I thought the fan was running to long when parked.
Would unplugging this cause the fan to cycle with the compressor?

 

[xlr8ngn]

Not sure what IC stands for, but when the AC kicks on, even if the engine is not warm, the radiator fan kicks on, as you need airflow across the AC condenser located in front of the radiator to cool it. No airflow across the condenser when the AC is running, the condenser heats up and the AC gets warm. Not sure if I answered your question.

 

[N2BUICK]

IC is intercooler to me. Radiator, condenser, intercooler, they all need air.
The question I'm looking for is, this fan is cycling on and off with the ac compressor. I don't think this should be happening. The fan is cutting off when engine is turned off also.
Thanks for the reply

 

[pacecarta]

cooling fan should run with ac compressor engaged , if it didnt the condensor wouldnt be properly cooled and the AC refrigerant high side pressure would spike up ,
theres a pressure switch in the line behind the ac compressor that engages the grounds to the coolant fan hi and lo relays when hi side pressure is present

 

[N2BUICK]

I'll try and rephrase this question.
Let's say your driving down the road, and your AC cycling switch turns the compressor off as it should. Do you think your radiator fan is also stopping?
In few moments when the compressor cycles back on, the radiator fan comes back on at the same time.
I don't think this is proper operation?

 

[xlr8ngn]

I'm not positive here, but in your scenario, if the car is below operating temperature, I would assume the fan is driven by the signal from the AC. If you car is above operating temperature, it will have a signal to run constant already, and the AC demand signal is redundant.

 

[pacecarta]

if your coolant isnt up to temp for fan to run from ecu command then yes fan will run on and off as ac clutch engages and it will run in hi speed

 

[N2BUICK]

Okay that good to confirm.
My coolant was 175 degrees and the radiator fan was cycling with the AC compressor. I am going to reconnect the three prong connector on the delay relay, and see what changes.

 

[salvageV6]

In A/C mode the fans are controlled by the High pressure side switch.
Low speed fan operates above 260 psi. and the high speed fan operates above 300 psi.
Obviously the coolant temp. is also a factor and the triggers are in parallel.
If the ECM commands low speed due to temp. set in chip that would also run the fan at low speed.
If the coolant temp. switch closes above 223 degrees or so (hot car) the high speed fan operates.
In order to check what is happening you would need to monitor the high pressure A/C port.
And you would need to know if you have all factory wiring and fans in place for the fan operation, it's modified on many cars out there.
The coolant fan delay relay works off temperature triggers not A/C pressures which normalize when the car is off.

 

[N2BUICK]

Your right, my AC seemed to be acting a little odd, this morning. I was adding R12, it's a seasonal thing.
The compressor was cycling off and on more quickly than it should?
OD temp in the mid 70's.
I will attach a high side gauge a see if it appears high.
Nothing bets having and empty system and adding the correct charge, after evacuation, I may need to do that.

 

[N2BUICK]

I plugged in the front 3 way connector, on the delay relay, and added R12. Things seem to be working better.
Now to tackle the airflow inside the car. Thinking it is the multi port vacuum device, in the heater control in the dash.