A Simple One... (Coolant Level Sensor)

[SwedishInside]

Just a confirmation really.

I have never thought my coolant level sensor has actually worked, so today I unplugged the sensor and started the car. No 'low level coolant' appeared on the dash, even after 30 seconds of waiting.

Am I to presume my sensor is actually dead?

Thanks

[swithers]

Common problem .. prob just wants a new sensor in the header tank .. Not very much money to buy.. (it fits in the bottom of the header tank). Hope this helps.

[phatboy130]

Ummmm No, not in my experience.

Wasn't until a few weeks after buying my 850 did I realise that my connector on the header tank for the coolant level sensor was unplugged, probably forgotten by the mechanic who did a cam belt change previously.

I asked why it didn't light up, the reason that forum members explained was thus:

The sensor only lights up the dashlight when the coolant level drops too low, allowing the "sensor switch" to complete the circuit.

If all is well i.e. the coolant level is correct, the sensor switch won't "close" to complete the circuit, and so the light stays off, same thing if it is just unplugged.

Does the light illuminate if you turn the ignition on? before starting up that is? If so, then the bulb in the dash is ok.

Hope that helps,

Jay.

[SwedishInside]

Originally Posted by phatboy130

Ummmm No, not in my experience.

Wasn't until a few weeks after buying my 850 did I realise that my connector on the header tank for the coolant level sensor was unplugged, probably forgotten by the mechanic who did a cam belt change previously.

I asked why it didn't light up, the reason that forum members explained was thus:

The sensor only lights up the dashlight when the coolant level drops too low, allowing the "sensor switch" to complete the circuit.

If all is well i.e. the coolant level is correct, the sensor switch won't "close" to complete the circuit, and so the light stays off, same thing if it is just unplugged.

Does the light illuminate if you turn the ignition on? before starting up that is? If so, then the bulb in the dash is ok.

Hope that helps,

Jay.

Thanks swithers but I believe phatboy130 has solved it.
I think my bulb in my dash have gone as I turned on my ignition (when all lights illuminate) and there is no low coolant level light.

I have also drained all my coolant today (not just for this job but my radiator has a hole in it... again!) and still the light doesn't turn on.

Thanks for this.
I will search how to now solve that low coolant light problem.

[phatboy130]

Glad I could help with my explanation, prob a good idea to check the bulb, tank socket connections, then sensor anyways just to be safe

Jay.

[SwedishInside]

Originally Posted by phatboy130

Glad I could help with my explanation, prob a good idea to check the bulb, tank socket connections, then sensor anyways just to be safe

Jay.

Thanks Jay.

[zaci]

Hi

Do you guys have any advice:

The coolant level light doesn´t illuminate when I turn the ignition on. The bulb is checked and it´s working.

The light will neither illuminate in the case that coolant liquid tank is empty.

Is this sensor problem or something else ( I think it´s something else since the light isn´t illuminating in any case)

Car is 1996 850 TDi

Thanks

J from Finland

[ruffday]

You could try shorting out the wires in the connector block that should illuminate it.

[Des O'Brien]

Did you check the float is moving up and down in the expnasion tank. Just inser a long screwdriver when tank open and see if it moves. Like all things treat them gently.

Anyone know if the sensor works on an open or colsed circuit. When I disconnected the sensor the dash warning notices came onin my S80 so this indicates it warns on an open circuit.

[harrypeacock]

Following various comments on the V70 coolant level sensor, and having the same problem myself, I can confirm that the sensor activates on a low coolant level as an open circuit. This can be confirmed two ways. Firstly unplugging the sensor will bring the light on. If you now poke a bit of wire into the socket holes on the "car" side of the connection, this will turn the light off.
Hope this helps