pornstarmatt

How often do your fans come on? Mine seem to come on a lot more then any other car i have owned. Even on cold nights, if the car is idling for more then a few minutes the fans kick on. Is this normal?

Since all i have is an idiot light for coolan i have no idea where my temps are at.

Matt

iKevin

Mine comes on alot too . . . I think they must have set it to come on at a lower temp than most cars since we don't have a temp gauge.

Driver_Lost

If your a/c is on or the defrost section (far right area) the hot condenser coil for the a/c will turn your fan on as needed.
I added gages to my RS 3.0, and the water temperature is very consistent around the 210F area no mater what.
The cooling fan is for both the water and the condenser, so either one can turn it on.

bB2NER

I'm used to it from my motorcycles doing it too.

pornstarmatt

210? Thats not high?

Jan06xB

Yeah that's boiling hot - should be 182 -186 and the fans kicks on at 195ish. Stay further back from the car in front of you when you stop to let some cold air into the grill!

vintage42

I have a ScanGuage electronic guage that taps the diagnotic port. It shows this:
137 Blue cold coolant light goes out
186 Normal driving temperature.
202 Fan comes on and knocks temperature down. Have only seen this after idling in traffic for several minutes, never while driving.

I doubt if the air conditioner or condenser actually turn on the fan. I think the condenser must first get hot, and then prevent the radiator behind it from rejecting enough heat to stay under 202, and then the 202+ temperature of the coolant is what turns the fan on.

Jan06xB

I have the Scangauge also but the fans will come on for the A/C even if the engine temp is 160 when the condensor coils get hot enough - apparently they are monitored. Or maybe if you sit still in one spot long enough it figures it out and kicks on the fans. I like to keep moving when I run the A/C so the condensor gets plenty of cooling and makes the compressor pump a lot less making it really cool in the cabin.

vintage42

Can the coolant be only 160 at the same time that the condenser is too hot?
The coolant can only be 160 during warm up, as the thermostat keeps it at 186.

pornstarmatt

You know I think my AC has been on everytime I notice the fans coming on. I'll pay more attention and see if thats the case. Thanks for the ideas guys.

Matt

Jan06xB

Sure park the car for a while then start it up and the engine is still cool but crank up the A/C and heat up the condensor.

Do it in a Prius and the engine is not even running and the fans come on - electric powered compressor for the A/C!!

vintage42

I had thought the condenser was in front of the radiator, and there was only one fan behind the radiator. But the Repair Manual at https://www.scionlife.com/tech/manual/?manual=xb04_0001 mentions a condenser fan. Where is the condenser located, and does it have its own condenser fan separate from the big fan behind the radiator?

Jan06xB

Yes the condensor is in front of the radiator to get the cooler air for the A/C and the radiator fan behind the radiator is also the condensor fan drawing air through both condensor and radiator. There is also a one way flap on the passenger side of the front grill to allow air to free flow through the condensor on that side since teh condensor is wider than the radiator. The one way flaps prevent hot air from flowing back out to the front of the car when stopped or in a tail wind.

vintage42

I have looked at the wiring diagram for the xB air conditioning system. It is a file called 034ac.pdf downloadable with a premium subscription to TundraSolutions.com. It shows no connection to any cooling fan, condenser fan, whatever.
I don't think an auto air conditioner is linked to a fan for its condenser. I think the condenser only gets cooled by whatever and whenever the radiator is cooled, without controlling it. For decades air conditioned cars simply had a condenser bolted in front of a radiator cooled by a belt-driven radiator fan.

Jan06xB

I was told that the ECU controlled it and turned it on when needed.

vintage42

Who or what said that? The ECU senses and controls engine functions. I don't think it has any connection to an accessory like the air conditioner.

Jan06xB

Yeah it does because turning on the A/C increases idle and it has to turn on the radiator fan somehow if the condensor is hot. Although it may have a separate thermal switch in parallel with the radiator switch. It also controls the variable assist in the power steering which is speed sensitive and not RPM sensitive.