ob.sebastien

Hello guy,

I've been searching on the internet for a while, but this is not easy to search : I have a wierd problem with my 2008 Civic Coupe (1.8L).

The A/C is working intermittently, that means it can runs for a while, but suddently stops working for couple of seconds, come back after etc. Here are my observation (not working since the beginning of the summer)

• Cold as ice when working (why I think I have enough gas?)
• Seems to works for a longer period when idling
• Disengaging when accelerating (red that was normal, done by the ECU after x% throttle)
• On the highway at constant speed, like 110 kph : can engage and disengage like 5-6 times per minute (I feel it in the car)
• Usually after 15 minutes it completly stops to work
• I've notice that even with the A/C off, when I put the front defrost the A/C turns on (yes I know it usually does this, but I've remove this fuction couple of year ago with a button combination trick and the light on the A/C button is still of
• When the A/C decides to stop working, there is nothing to make it start again, the only thing is to turn off the car and let it cool for a while. No relay clicking when pressing the A/C button, nada, absolutely nothing changes.

I don't know if it's related, but I've noticed that the rad fan starts and stops intermittently also (not related, when the A/C is off) in a strange way and not always. For example in a drive through, the fan can be off 10 seconds, on 10 seconds, off 10 seconds. Another suspicious thing : the car was really hard to heat this winter, thought it was the thermostat, but in fact I'm pretty sure the rad fan is working even if it's -20 in a strange pattern...

Like I said, when the A/C is working, it's working fine so I'm more thinking of an electrical problem than mecanical, like a temp sensor or I don't know, but I really don't know where to start. The A/C compressor is not too old also, I've changed it for a new one 3 years ago I believe.

Thanks for the help, if you need video, measurement, etc just let me know !

ezone

ALL of this sounds like normal and correct operation.

Compressor cycles on and off to maintain specific temperature range in the evaporator core
BOTH radiator fans must run at the same time the compressor clutch is engaged,
BOTH radiator fans must also run whenever the radiator temperature is high to prevent engine overheat.

No, this is a pretty typical complaint with that small engine in extreme cold temperatures. Low speed and idling just doesn't burn enough gasoline to make good heater output, but if you get on the highway for a while the heater output is pretty good.

Need to observe, AFTER this system has quit working, you try to turn the AC off then on again (without letting it cool off): when you try to turn on the AC do both radiator fans still turn on as they should?

If fans do NOT turn on immediately: Check if thermal protector is open circuit

If fans DO turn on immediately:
I would inspect the clutch relay
I would inspect the Clutch Coil resistance, for possible open circuit
check the air gap (clearance between clutch outer plate and the pulley) may be too large due to wear. Possible fix is to remove clutch plate and remove a shim to decrease the air gap.

ob.sebastien

This is what happen, the fan doesn't turn immediately... Please give me more detail about the thermal protector, where to find it and to test it

Thank you

ezone

Sorry it took so long

Wire Harness to AC compressor contains 3 red wires.
Connector is mounted on or next to the alternator. (at least you can check this without crawling under the car yet)
Center wire is for the clutch field coil, outer two wires are for the thermal protector.
Ohm test the two outer wires, should show continuity (zero ohms resistance or very close to zero)