Gen 5 Celica . Engine Radiator Fan always on

[TJPStones]

Hi There

 

I have a Gen 5 Celica.  I have had a cooling issue which i think i have resolved with a new rad and flush out,  But my radiator cooling fan is permanently on. I think the problem must be in the sensor switch or relay, but despite having a haynes manual i still cant quite work out exactly where the sensor switch or relay is. The engine is 1998cc so it's a 3S-GE engine so the sensor switch is supposed to be on the thermostat housing, but i seem to have 4 or 5 different sensors in and around this area. 3 at the front, one at the rear and one above left of the 3 in a row if anyone can advise or guide me on which of the sensors is the one for the fan, and where the fan relay is that would be great. (and what all these other sensors are also would be good.)

 

thanks

Tony

[CheltGirl]

I'm sure someone will be along soon to shed some light on the various sensors for the fan identification. I'm not so familiar with the 3S-GE engine. There should be a sensor somewhere going in to a pipe that is carrying the coolant round I believe?

[TJPStones]

thank you.  according to Haynes manual it is mounted on the thermostat cover , but i have no idea which one it is.

 

thanks for your response.  

[Old Red Celica]

Have you tried unplugging each sensor in turn, only one at a time. The haynes manual may show how many wires go to the fan temp probe.

[TJPStones]

thank you . let me try that

[TJPStones]

Thanks tried that. in each case the fan kept running.  Maybe the relay.  will see if i can get a replacment relay. sincerely hope its not a problem with the wiring loom 

 

thanks again

[_Chris_]

Haynes manual is talking rubbish. If you look in the sticky topics at the top of the gen 5 section you'll find the genuine Toyota ones in pdf form.

 

The sensor which drives the fan is on the bottom tank of the radiator, next to the big water outlet pipe. It's a normally closed sensor, i.e. it opens to bring the fan on. If you've forgotten to plug it back in after changing the radiator the fan will always run.

 

If that doesn't cure it, there is a sensor in the aircon pipework at the back of the engine bay, passenger side, near the diagnostic connector. Again, that brings on the fan permanently if it's unplugged.

 

[TJPStones]

thank you so much.  the sensor at the bottom of the rad is in, but i will try changing that sensor , as it sounds like it is an inhibitor sensor and the fan will run even if its plugged in if the sensor is not working . to be honest i am on my 3rd rad on this czar over 30 years, so the sensor has been in and out a few times, and maybe the clip onto the sensor is faulty.

 

thanks for pointing me in the right direction .

 

 

Tony

 

[_Chris_]

You can check the control system by linking the 2 pins in the loom and check the fan goes off. If it waqs working before the rad change it's most likely the sensor was damaged swapping it over.