ST165, what sensor controls fan?

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UtahSleeper

Active member

• Jul 26, 2015

• #1

So, simple question.

Is it the temp sensor at the bottom of the radiator that controls the fan?

 

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zaluss

Member

• Jul 26, 2015

• #2

UtahSleeper":1f8g9zg0 said:

So, simple question.

Is it the temp sensor at the bottom of the radiator that controls the fan?

Click to expand...

That sensor will determine when to engage the fan depending on the temperature of the coolant. If the sensor is disconnected, the fan will always engage (even with the engine off, ignition set to ON).

 

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Awesome-Trac

New member

• Jul 26, 2015

• #3

So a bad sensor will cause the same symptoms correct cause mine stays on with just the ignition on

 

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zaluss

Member

• Jul 27, 2015

• #4

Awesome-Trac":28wrpr21 said:

So a bad sensor will cause the same symptoms correct cause mine stays on with just the ignition on

Click to expand...

I believe so as a Toyota fail safe.

 

underscore

Well-known member

• Jul 27, 2015

• #5

Yep, bad sensor or broken wire will hold the fan on.

 

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UtahSleeper

Active member

• Jul 27, 2015

• #6

Thanks, just wanted to verify. My fan stays on and I am about to replace my radiator. Would rather replace the sensor while I am doing this.

 

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UtahSleeper

Active member

• Aug 10, 2015

• #7

Well, I replaced my sensor and the fan is still on all the time.

I will try and check the wiring, but could it potentially be a relay?

 

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zaluss

Member

• Aug 10, 2015

• #8

UtahSleeper":21j2j4o4 said:

Well, I replaced my sensor and the fan is still on all the time.

I will try and check the wiring, but could it potentially be a relay?

Click to expand...

If the AC has been removed from the car, that will trigger the fans to go as well. You'll need to connect a sensor on the firewall (or short it) to stop this from happening.

http://www.gtfours.co.uk/ > How To > Remove Aircon

 

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UtahSleeper

Active member

• Aug 10, 2015

• #9

I did not know this. Thanks I may try this or just reconnect the wires to the ac compressor and see if it fixes.

I plan on eventually trying to get the 215 compressor hooked into the stock pieces, so I left it installed on the block.

Is shorting it as easy as just jumping the plug with a wire?

 

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RedCelicaTRD

Moderator

• Aug 10, 2015

• #10

Compressor wires shouldn't matter. It's the pressure switch on the a/c lines up by the firewall that you will need to make sure is plugged in.

When I had a fan that was stuck on, it was caused by a broken wire by the fuse box.

 

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UtahSleeper

Active member

• Aug 10, 2015

• #11

RedCelicaTRD":fhutkiw1 said:

Compressor wires shouldn't matter. It's the pressure switch on the a/c lines up by the firewall that you will need to make sure is plugged in.

Click to expand...

Can you just jump the connector or does it need the switch? PO removed all the lines and such, so there is no switch to be had. :/

 

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alltracman78

Active member

• Aug 10, 2015

• #12

You can jump the connector. That's all the switch does [it disconnects the "jumper" if the pressure is to high].

 

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RedCelicaTRD

Moderator

• Aug 11, 2015

• #13

There is a factory jumper for the ST185 so I assume the ST165 has one also. They have been discontinued, but if you can find a car without A/C in the junkyard it might have the factory jumper still on the harness.