Technical Sei coolant temperature sensor

[g4jvf]

Guys
How does the coolant temperature sensor work on a 2000 SPI SEI.

I thought it was just an on off device relative to temperature but on my SEI,
I'm getting the coolant temperature warning light flickering on now and again.
Odd thing is, sometimes it's on but very dim and brightens up at other times...

Fan is working OK and I don't think it's over heating...
Never happened before but it's been coming on a few times since I got the car back from having a Lambda sensor replaced to get it through the MOT emission test.

Just seemed odd that the brightness of the warning lamp varies

Thanks for any suggestions

Philip

 

[fingers99]

From memory it's just a switch which goes "on" at a given temperature. Chances are that it's switched on the earth side, so I'd suspect frazzled insulation somewhere.

 

[g4jvf]

From memory it's just a switch which goes "on" at a given temperature. Chances are that it's switched on the earth side, so I'd suspect frazzled insulation somewhere.

Thanks
I'll have a good look round to see if I can spot anything..

Is the sensor the one near the top left rear of the engine looking from the front
about in the area where the dip stick handle is?
It's got a single wire coming out of a spade terminal or maybe that's the oil pressure switch.

 

[blu73]

yep that is the one for the gauge.

 

[g4jvf]

yep that is the one for the gauge.

Thanks mate

 

[Duncan]

Have you only recently changed the sensor or bought the car?

Only asking cos I work in a motorfactors and we use Autocat for our parts lookup which is a very common system across the UK. Several of the aftermarket brands have the wrong listing for the Seicento and list the Cinquecento sensor which caused the light on my Seicento to act in similar way to what you are describing.

 

[fingers99]

That's a good point.

The one for the guages is a variable resistor (maybe a thyristor?) so might cause the intensity of the light to vary.

A call to Fluffy at eurocarcare.net will get you the right one.

 

[g4jvf]

Thanks guys
I've had the car from new, 2000 and it's just reached 67000 miles

Dont think the sensor has ever been changed so Ill grab a new one
and replace it if it will come out OK...

Does it just power the warning light direct or does it go via the computer I wonder....

 

[fingers99]

If SPI it's direct. If MPI I'm pretty sure it's via the ECU.

 

[cc1]

The Spi Seicento has a sensor for the Ecu and a thermo switch for the overheat light.

 

[g4jvf]

The Spi Seicento has a sensor for the Ecu and a thermo switch for the overheat light.

Thanks for that...
So, if the thermo switch is the one up near the top of the dip stick then
any ideas where the other one is?

 

[cc1]

Thanks for that...
So, if the thermo switch is the one up near the top of the dip stick then
any ideas where the other one is?

At the other end of the head.

 

[g4jvf]

At the other end of the head.

Thanks
Will go have a look see