Coolant sensors.

[AndyR]

Hi does anybody know if my Astra G z16xe should have a heat sensor in the radiator to inform the electric fan to kick in when the coolant gets hot in traffic. 

I have found a plug that comes from the loom beside the radiator, but there is no where to connect it. And my fan does not start at all in traffic. I have seen videos on YouTube showing that there is a choice of radiator fan switch's, and if you get the wrong one it will be constantly running.

I just haven't got any fan switches at all.  

Regards Andy. 

[Vauxhall Owners Club]

Hi Andy

Can you take photo of the plug so it shows the location of it

Cheers,   Trevor

[AndyR]

Hi Trevor, picture of said plug. Hangs behind nearside headlight beside radiator.

[Vauxhall Owners Club]

It looks like it should plug into a sender unit, which may have been present on the previous radiator (if replaced) and not equipped on the one that is in the car.

I would also move it around in the radius of its available length to see what sensors or plugs are in the area

[AndyR]

Cheers Trevor,  I did wonder if the rad had been replaced. I will have a check around to see if there is somewhere it connects to. 

When it stops raining and blowing a gale.

Andy.

[AndyR]

Well I've been servicing the car today and had a look about with the wiring. And I have found exactly the se plug behind the horns, swinging in the breeze. So I'm guessing they could be for driving lamps.

 

[Vauxhall Owners Club]

Ah thats a possiblility Andy.

I did also wonder if it could have been an Ambient Air Temperature Sensor which are usually mounted behind the bumper to get the air flow and measure the outside temperature. But there would only be one plug so if you have two plugs then chances are it is what you say, driving lamps.

[AndyR]

It's about the only idea I could think of with having the same plug either side. The air sensor is one plug, and it's right in the middle of the bottom front bumper grille.  Got a feeling I'm going to have to hard wire the fan to a manual switch.  

Would the coolant fan be the one on the inside of the engine bay? And the aircon fan the one on the front?

[Vauxhall Owners Club]

Yes thats right Andy, if you were going to wire a switch to the fan then something like a Kenlowe fan kit would be ideal modification to go with

[AndyR]

Cheers Trevor,  a job for the weekend  me thinks. I will give it a live feed first to make sure it's working. And if the fan has died, I'll replace with the one from old car. 

[AndyR]

Well i had a play with the electric cooling fan today. Putting a direct live feed to it, and it worked fine. But it doesn't kick in when engine gets hot in traffic. 

I have no Thermo switches on the radiator itself, but there is what looks similar to the heater blower resistor on the fan . Could it be this at fault?. Also checking the fuse box, and found that the fuse which I think relates to electric fan is missing. So brother in law is going to do a circuit test tomorrow to see if there is any power to the fan.  Will then replace fuse and see what happens. 

[AndyR]

 

This is the item I am wondering about.

[Vauxhall Owners Club]

looks like a fan speed resistor pack to me as has a heat shield for when it gets warm and also protects the resistors

[AndyR]

Thanks for the correct description Trevor,  now I know what to look for.

[AndyR]

***UPDATE***

I have found out that the Astra G mk4/5, doesn't actually have a separate switch/sender for the electric cooling fan in the radiator. 

It is however integrated in with the sensor for the temperature gauge, and apparently the ECU senses the spike in temperature and tells the fan to kick in. But as mine isn't doing this because my gauge is not reading correctly,  the ECU isn't sensing the engine temperature properly,  hence why I've had some over heating issues.  

So this morning I have ordered a new temp sensor, and will be replacing the old one. 

I'm going to leave the fan hard wired for a bit just to make sure things are working as they should.

Sorted in time for the lovely hot spell. 🌡