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Location:
Sydney
Registered:
November 2004
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Celica Fan always on? (ST162)
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Mon, 01 November 2004 00:30
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Hey all
Got a problem i need to diagnose. The driver's side fan at the back of the radiator of a friend's 88 Celica (ST162) is always on when the ignition is in the "on" position. It's fairly loud and can be heard in the cabin. It seems to be a aircon fan, because it's marked with a "denso aircon" sticker so i think it is. I've removed the relay for A/c fan from the aircon fuse box, and it stops, but i don't think this is very good. The relay was fine from testing it with the multimeter.
I think that i have to replace the refrigerant temperature sensor, but i'm not sure if this needs to be done by an air-con shop because i will lose the gas from the system when i do it. Would i be right with this guess? Also, where is the sensor in the system? Is it in the compressor or the evaporator? Toyota said something about a new temp sensor, i think they said it goes in the TX valve, or it's a new TX valve.
Or i could be completely wrong and the fan should always be on, and perhaps it just needs to be replaced because the bearings are shot (explaining why the damn thing is so loud)
Any ideas?
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Toymods Club Treasurer
Location:
Sydney
Registered:
May 2002
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Re: Celica Fan always on? (ST162)
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Mon, 01 November 2004 00:39
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Are the A/C switch and under dash fan on inside the car?
If so, this will turn on the rad fan(s).
If not, the temp sensor for the radiator could be playing up, meaning its always on. I don't know where this is on your car though.
If you've got a multimeter test the rest of the circuit.
generally the temp switch will earth out the fan.
You should have +12V to the fan whenever the ignition is on.
The other side should be earthed when:
coolant temp is high or A/C is on.
If its constantly earthed, there is a short somewhere, or possibly someone has bypassed the temp switch because they couldn't be bothered replacing it when it died.
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Location:
Sydney
Registered:
November 2004
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Re: Celica Fan always on? (ST162)
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Mon, 01 November 2004 00:46
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Cheers, i'll look at it. The A/C switch is off, and the other fan appears to work correctly, i'll check the voltages etc and see if i can find that pesky sensor and replace it (it's only a $65 part not bad). My guess is poor wiring or the sensor, i just didn't have the reference manual handy.
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Toymods Club Treasurer
Location:
Sydney
Registered:
May 2002
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Re: Celica Fan always on? (ST162)
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Mon, 01 November 2004 00:55
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I wouldn't replace the sensor at this stage.
Just see if its been bypassed.
BTW, it's probably mounted in on the rad end tanks.
If you want to check it: remove it (you'll lose your coolant though), dunk it in freshly boiled water to check to see if there is continuity across it with your multimeter.
If not, then definitely replace it.
If one of the sensors in your A/C is playing up, generally the A/C simply won't come on (ie the compressor won't engage)
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Location:
Sydney
Registered:
November 2004
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Location:
sydney
Registered:
March 2003
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Re: Celica Fan always on? (ST162)
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Mon, 01 November 2004 01:06
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theres is no temp sensor
there is a hi and low pressure sensor
the fan on engine side of radiator is the engine cooling fan
if the hi/low pressure sensor on the a/c plays up or u have a break in wiring
or the faqctory thermo sensor plays up or wiring breaks then this fan will turn on
so i think its not the a/c fan u talk about
cause the a/c fan is one just behind grill
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Toymods Club Treasurer
Location:
Sydney
Registered:
May 2002
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Location:
Adelaide - Race Central
Registered:
June 2004
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Re: Celica Fan always on? (ST162)
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Mon, 01 November 2004 06:54
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Hey buddy,
That happened to my 162 aswell, I'm pretty sure that its the Temperature sensor for the radiator coz when they changed my water pump, they changed the thermostat aswell and it stopped right after.
Cheers
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Location:
Menai area of Sydney
Registered:
June 2003
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Re: Celica Fan always on? (ST162)
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Mon, 01 November 2004 10:41
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I had the same problem with the engine fan staying on after an engine swap in a Rolla. Turned out there was an earth wire behind the fuse box in the engine bay that looked OK but wasn't earthing properly. Check all the earthing wires from the loom, especially any near the relays.
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