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Discussion Starter #1
Hi, I have a question!
I have RAV4 2009 V6 (Sport), can any one tell me how radiator and AC FAN works?
When I start car (Without turning on the AC), when radiator FAN should works?
Is it one FAN should work or the both FAN?
When I turn on the AC, how many FAN should work?

I need to know how original/factory setting is?

Regards.
 

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According to the wiring diagram (assuming I have the right one), they are on the same shared circuit. They are switched on from a signal from the PCM when it determines the temperature is too hot. They will not run on a cold engine.
 

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It seems the fans will cycle often even when the AC is off, when you're on "defrost mode" is on your heater setting. Turn the mode to floor only and the fans should only cycle when the engine gets hot.
 

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Discussion Starter #6
According to the wiring diagram (assuming I have the right one), they are on the same shared circuit. They are switched on from a signal from the PCM when it determines the temperature is too hot. They will not run on a cold engine.
So my question is, when I start the car while AC is off. After the engine heats up and reach to threshold temperature, sensor will send the signal to run the FAN. I want to know, at that time, in my RAV4, one FAN will start or both FANs will start together? (Remember AC is off)?
 

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Discussion Starter #7
It seems the fans will cycle often even when the AC is off, when you're on "defrost mode" is on your heater setting. Turn the mode to floor only and the fans should only cycle when the engine gets hot.
Thanks, Just want to clarify that I am talking about Radiator and AC cooling fan in the Bonnet.
So want to know, While AC is off, when I start the car and engine heats up and reach to threshold temperature, One FAN will start or both FAN will start working in the Bonnet?
 

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Thanks for the clarification. Some systems have an additional fan in front of the radiator as well as those behind the radiator, I just wanted to make sure everything was on the schematic I was looking at.

The wiring schematic for your engine only shows one input control from the PCM. Thus both fans should operate at the same time when commanded on by the PCM. If only one works, it is possible to have a fuse or wiring issue to one fan. That could be power or ground side
 

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Discussion Starter #9
Thanks for the clarification. Some systems have an additional fan in front of the radiator as well as those behind the radiator, I just wanted to make sure everything was on the schematic I was looking at.

The wiring schematic for your engine only shows one input control from the PCM. Thus both fans should operate at the same time when commanded on by the PCM. If only one works, it is possible to have a fuse or wiring issue to one fan. That could be power or ground side
Thanks for the answer.

Let me give you a history. Actually my car has AC issue and I changed the AC compressor here in Nigeria. They guy who changed it didn't use the right one and then tempered the wiring to make sure FAN works (they directly connected the radiator fan with battery), so even I turn the key , FAN starts cycling even before I start the engine.

I order to fix all this, I contacted another AC technician, he than fixed the right compressor, but fail to connect the fans connections as factory fitted. I tried another electrician, but to fix the fan connection, he spoiled the Amplifier module. (When I contacted another electrician) he told me that amplifier module (Temperature control module) is faulty.

As the amplifier module was not available in local market, I ordered it from US. Yesterday Technician fix the amplifier module and made all connection according to factory diagram or factory setting.

As of yesterday, the connections are, when I start the engine, both fan will be off, after some time when the engine heat ups, both fans will start cycling. When I turned on the AC, both fans will start cycling as soon as I turned on the AC.

Just want to confirm if the current above setting is right like factory setting?

I am confused as some places I read that, when engine heat up , one fan (radiator fan) should cycle not the both.

So I want to know, in case of RAV4 2009 V6 Sport, which fan setting is right?

Appreciate to get the right factory setting for my car model? Thanks
 

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Many thanks KWA for your detailed answer - it certainly looks like you have had to work hard to get things correct - well done on sticking to it.

I am unable to find the programming for the PCM module, so I do not know what it is supposed to do. However, this is my thought process based on the Toyota wiring diagram, and the logic I know from another manufacturer.

The wiring diagram (I am assuming it is correct, but it is not unheard of for it to be wrong!!!!), shows that both fans work together when commanded on by the PCM (from the temperature sensor), so from what you have described, I believe yours are working correctly.

On another system (BMW), the logic is for the AC fan (it is in front of the radiator, hence my question), to work fro approx 20 seconds on start up with AC on, it will then stop. AC puts an additional load on the cooling system so having two fans is good - especially in hot climates such as yours.

I have just reread your post, and as far as I can determine, you are now working as factory. Of course, I would, of course, defer to someone who knows the full PCM program logic. The AC wiring diagram does not have a direct link to the fans, only via the PCM.

In summary, both of your fans appear to be fine now and seem to react to different inputs, so I believe the system is all good now
 

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Discussion Starter #11
Many thanks KWA for your detailed answer - it certainly looks like you have had to work hard to get things correct - well done on sticking to it.

I am unable to find the programming for the PCM module, so I do not know what it is supposed to do. However, this is my thought process based on the Toyota wiring diagram, and the logic I know from another manufacturer.

The wiring diagram (I am assuming it is correct, but it is not unheard of for it to be wrong!!!!), shows that both fans work together when commanded on by the PCM (from the temperature sensor), so from what you have described, I believe yours are working correctly.

On another system (BMW), the logic is for the AC fan (it is in front of the radiator, hence my question), to work fro approx 20 seconds on start up with AC on, it will then stop. AC puts an additional load on the cooling system so having two fans is good - especially in hot climates such as yours.

I have just reread your post, and as far as I can determine, you are now working as factory. Of course, I would, of course, defer to someone who knows the full PCM program logic. The AC wiring diagram does not have a direct link to the fans, only via the PCM.

In summary, both of your fans appear to be fine now and seem to react to different inputs, so I believe the system is all good now
Thanks Alot Bigphill555 for detail feedback.

Lets hope someone else in the forum can confirm this that in RAV4 2009 V6 Sport how radiator and AC Fans work (without AC on and with AC on)?
 

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I think Bigphil555 is correct that both fans come on together. I've never noticed if only one of mine come on at a time yet.
Either way, don't worry about it. Only worry if your temp gauge gets to the red zone and the fans haven't come on yet. Good luck......
 

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Discussion Starter #13
I think Bigphil555 is correct that both fans come on together. I've never noticed if only one of mine come on at a time yet.
Either way, don't worry about it. Only worry if your temp gauge gets to the red zone and the fans haven't come on yet. Good luck......
Thanks Kevin. Just want to confirm you have same model of RAV4 like mine? (Toyota RAV4 2009 V6 Sport)?
 

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No, I have an 08 limited with the I4 engine, with two fans on the rad.
 

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Hope someone having RAV4 2009 V6 Sport can comment on this :)
I highly doubt that the trim, Base, Sport or Limited, makes any difference, or the year for that matter. Or even the car brand since a two-fan system is nearly universal these days.

And I think you've found someone who figured out the mess and fixed it for you.

The way it should work is upon starting the car (AC off) no fans should come on. In fact the instructions for many repair issues start with, "With the AC off, let the engine idle until the fan(s) cycle on." That gives a stable warmed-up temperature for other tests.

Typically the fan(s) are controlled by a temperature switch at the bottom of the radiator. On some cars that switch may turn on one fan and the AC adds the other. In this case apparently the fans are wired in parallel so you'd either have none or both running.

Summary:
AC off = fans cycle as needed to maintain engine temperature.
AC on = fans run continuous.
 

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Discussion Starter #17
I highly doubt that the trim, Base, Sport or Limited, makes any difference, or the year for that matter. Or even the car brand since a two-fan system is nearly universal these days.

And I think you've found someone who figured out the mess and fixed it for you.

The way it should work is upon starting the car (AC off) no fans should come on. In fact the instructions for many repair issues start with, "With the AC off, let the engine idle until the fan(s) cycle on." That gives a stable warmed-up temperature for other tests.

Typically the fan(s) are controlled by a temperature switch at the bottom of the radiator. On some cars that switch may turn on one fan and the AC adds the other. In this case apparently the fans are wired in parallel so you'd either have none or both running.

Summary:
AC off = fans cycle as needed to maintain engine temperature.
AC on = fans run continuous.
Thanks Dr. Dyno for your input. Now I consider my car FANs are working fine as factory setting and connection is correct.
 

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Generally not good to have the fan wired directly to the battery. On some cars (don't know about Toyota), it can be difficult to get the car to shut off because when you turn the key off, the momentum of the fan allows it to run for a half a second and that actually turns the fan into a generator. The voltage created can cause run-on of the engine. I came across that on a car a few years ago and even some mechanics were stumped as to why the car would not shut off after the key was taken out.

I don't have a 6 cylinder, but my RAV fan turns on when the coolant hits 206 degrees F, according to my scanner and then it shuts off at 196 degrees F. This is without the AC or defrost being on. With the AC/defrost on, the condenser fan starts within seconds of the AC or defrost button being turned on, and the coolant fan usually starts a minute or two later.
 
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Discussion Starter #19
Generally not good to have the fan wired directly to the battery. On some cars (don't know about Toyota), it can be difficult to get the car to shut off because when you turn the key off, the momentum of the fan allows it to run for a half a second and that actually turns the fan into a generator. The voltage created can cause run-on of the engine. I came across that on a car a few years ago and even some mechanics were stumped as to why the car would not shut off after the key was taken out.

I don't have a 6 cylinder, but my RAV fan turns on when the coolant hits 206 degrees F, according to my scanner and then it shuts off at 196 degrees F. This is without the AC or defrost being on. With the AC/defrost on, the condenser fan starts within seconds of the AC or defrost button being turned on, and the coolant fan usually starts a minute or two later.
Thanks for the feedback. When coolant hits 206 degrees F, is it one Fan turn on or both fans turn on (without AC on)?
 

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Thanks for the feedback. When coolant hits 206 degrees F, is it one Fan turn on or both fans turn on (without AC on)?
One fan, left side or driver side (US spec'd).
 
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