2002 Honda Civic Intermittent cooling

Hi jsinnott,

Thank you for the donation.

I need to clarify this. You mentioned the AC is blowing HOT, is it hot as if the heater is being turned on or just that it is not cooling sufficiently?

If hot as if heater has been turned ON, the fault should be with the air mix door control circuit.

If it is not blowing cool sufficiently, it could be caused by inefficient condenser cooling. Check if the condenser fan is turning on when the AC compressor is engaged.

Hi James,

Good job done. You have confirmed the fans are operating and the problem is not due to the heater system interfering so we can get to the diagnostics. Who knows, we might be able to show the dealer some tricks.

The 2 large fans are known as radiator and condenser cooling fans, with the radiator fan at the transmission side. They would only come on when the AC compressor is engaged or when the engine operating temperature is hot enough to activate the fan switch.

The main problem should be the compressor cutting out when vehicle is operating at low speed and there are a few possibilities.

1. Low engine idling speed.
What is the idling speed when engine is at operating temperature?
Is there any clicking noise from the engine and does the idling speed keeps fluctuating when it is happening?
You can check this when the AC starts blowing warmer air. Note if the AC switch green light is flickering for a start.

2. Weak compressor. The compressor is able to provide cooling only when it is turning at a higher engine speed and when slowing down or stopped, the engine speed is low thus the inefficient cooling.
To test this, when AC is not blowing cold, check if the compressor is engaged, visually inspect if the compressor clutch is engaged and note if the cooling fans are running.
If clutch is engaged and fans are running, increase the engine rpm to 2000 and note if the cooling efficiency is improved.
Did the dealer check the low and high pressure at idling and when rpm is increased to 2000 rpm? This test should be able to tell if the freon level is correct, any operational malfunctions and possble cloggings in the system.

3. Freon, lack of it or over filled. Lack of it would be the more likely cause as overfilling would have the compressor cutting in and out while driving as well and the cooling would not be good as well.

4. Inefficient condenser cooling. As fans are working, it could be the condenser fans sre clogged with mudm dirt etc so give it a viasual inspection to confirm this.

5. Electrical circuit or component malfunction. Test would have to be carried out and if you have a DVOM and is into DIY, we can assist in provding the procedures.

Check the above and if there are any information that you think can be of assistance, please let me know.

Was any repairs done prior to this happening?
When AC is not blowing cold, does it improve when the vehicle starts moving?

Hi James,

Based on the latest detailed description of the problem, the compressor is cycling on and off or is not working intermittently and possible causes are :

1. Excessive freon in system
2. Bad compressor clutch. A test of the funtionality of the clutch and its coil resistance would be required.
3. Bad PCM. The AC control circuit from the Power Control Module is bad. When AC cuts off, it sometimes requires some on/off operations to get it working.
4. Failing compressor clutch relay.

Let the dealer check on the above possiblities.

Hi James,

Thank you for the update. Glad to know that you have solved the problem.

Thank you for using 2carpros.