14 replies to this topic

[acngnr]

When idling with the shifter in Drive, the AC compressor on my 2005 Matrix XR goes on and off frequently. Here is what is going on:

Compressor kicks on, RPM goes up, compressor kicks off after 10 to 15 seconds, RPM goes down, then compressor kicks back on again after 15 seconds.

Has anyone else seen this problem or know what is causing this?

Thanks.

[KWH]

Usually means low charge or it's just cycling. You have the A/C or defrost on?

[acngnr]

AC is on when the Idle RPM keeps going up and down. This idling issue goes away as soon as the AC is shut off.

[KWH]

Sounds like it may need a shot to fill it. Hope you don't have any leaks. If it does this constantly with the A/C or defrost on, I'd think it was low on R-134a.

[2zzge]

its normal. turn the AC on full bore. everything to max. this will cause the AC to stay on longer...but it will still cycle.

our AC is pretty small and at idle doesn't kick out much juice (our motor is pretty weak at idle and so is the alternator output). the A/C turns on and off rather often to try and stay at a set temp inside the car (depends on where you have it set for). this is why i said to turn it on full-bore-max cold to see if the compressor stays on longer. it should. if it doesn't, (instead turns on/off every few seconds) then i would get it looked at by a pro. it may have a leak, or some sensor is malfunctioning. (loose wire etc)

otherwise its just a weak motor and a weak A/C as stock.
:cool:

[Frankensteineken]

That's normal. If it is low on charge, the compressor won't cycle.

[Roxtar]

pfffft!

SUNROOF BABY!!!!

only AC when it's raining in the summer. 8)

[mistamatrix]

Also, keep in mind that if your HVAC setting is either at 'defrost' or 'defrost+feet', it will automatically use your AC even if you haven't turned the AC button on.

[dominator]

Indeed... AC is activated at just past the 'Floor' setting. I've modified the control knob's cam to have AC on only past 'Floor/Defrost' blend position.

[ellisdustin]

Mine does it too. I thought there was a problem with it but from the posts here it sounds pretty normal. Guess I won't worry.

[dominator]

It is normal, there's a little toggle switch on top on vent control knob beside the main A/C switch that is actuated by a plastic cam lobe on the rear of vent control knob...

[phil]

I have an 05 Corolla, but I noticed the fan behind the rad would come
on and off every 10 to 15 seconds, doesn't matter if the A/C switch is on or off. And if I turn the fan speed switch to OFF, the fan will not turn on.

[dominator]

phil said:

I have an 05 Corolla, but I noticed the fan behind the rad would come
on and off every 10 to 15 seconds, doesn't matter if the A/C switch is on or off. And if I turn the fan speed switch to OFF, the fan will not turn on.

Is that with the heat on, which assists in engine cooling? You radiator fan should eventually come on regardless of blower fan switch position...

[Edge04]

It's normal. I have noticed it on every car I have owned. Depending on the system, it is more loud or prominent than others.

[2zzge]

there's a wire connect behind the fan control knob, that if you disconnect said wire(s), the AC won't come on when you turn the defroster/heater on.
i've disconnected mine and the AC no longer comes on when i have the heater/defroster on.

as for the radiator cooling fan, that is on a seperate circuit and is controled by a thermostat/engine temp sensor. that isn't controled by us. with the key on it can come on at any random time.
(after running the engine for a while, turn it off. then turn the key to the "ON" position. the fan will turn on and after a while turn off...depending on how hot your engine is, it may turn back on/off again in cycles until the engine has cooled down.)

the AC cycling on/off can be limited by unplugging that wire i spoke of at the top of this post. it will still cycle when you have the AC on, but not when you have the fan on for any other reason.