Technical Coolant Sensor Wirediagram

[Peerke]

I have a Sei Sporting from 1999. The overheating light turns on when the engine just opens the radiator valve. We replaced the (1-wire) sensor, this didn't help.


Before this happend we had a faulty oil-pressure sensor and I (by misstake) took out the coolant sensor. After fitting this back and replacing the oil-pressure sensor all looks fine. After a short ride the temp-light went on.
So we did some testing the max temp of the water is 96 degrees. the cooling system seems to work fine except for the sensor circuit.


Does anyone know how the wiring looks like?
The 1-wire sensor seems a NTC/PTC (negative temperature cooficiant resistor) so the other part of the circuit could be broken?


Kind regards,


Peter

 

[David C]

The usual issue is that someone has used the variable temperature sensor from a Cinq (which has a gauge) instead of the temperature switch from a Sei (which only has a light).

Does the warning light come on dim and get brighter?

 

[fingers99]

:yeahthat:

If you want the diagrams they're all in the Seicento Technical Manual in the Downloads section. Script is in English, but wiring diagrams are in Italian for the colours.

 

[Peerke]

@ David C,


"Does the warning light come on dim and get brighter? "


Yes the light comes on dim and then turns brighter.
This was also the case with the old sensor when the light turned on.
Before i removed the sensor all apeared to be working fine.

 

[Peerke]

Found the manual, thanks

 

[David C]

@ David C,


"Does the warning light come on dim and get brighter? "


Yes the light comes on dim and then turns brighter.
This was also the case with the old sensor when the light turned on.

You have the wrong sensor then.
The "sensor" on the Sei is just a switch, so is either on or off.

 

[Peerke]

You have the wrong sensor then.
The "sensor" on the Sei is just a switch, so is either on or off.

In the autodata are only 3 sensors, 1 as a 1-wire, 2 as a 2-wire.
In the engine was a 1-wire, that would mean that the previous owner changed it with the wrong one.


I'll take a look in the tech manual to see if there is the right sensor.

 

[fingers99]

Easy enough to test with a pan of water, a stove, and an ohmeter. Correct sensor for Sei will simply go on = no continuity a certain point. Wrong sensor resistance will decrease as temperature increases.

 

[Peerke]

Found it in the wiring diagram.


Are the original part numbers also located in the manual?
On the original switch is no indication what so ever.
In the current partprograms at the garage and roadservice only mention the new 'gauge' sensor and not the on/off switch.


Do you know where to look if i want to fit an gauge (i gues that would be a indicator with a scale on it)?

 

[David C]

In the current partprograms at the garage and roadservice only mention the new 'gauge' sensor and not the on/off switch.

It seams that most after-market suppliers list the wrong one. Quick check is that if they list the same one for a Cinq, it is not the right one for a Sei..!

I think it is p/n 7588920

 

[fingers99]

:yeahthat:

A FIAT dealer will be able to get you the right one by VIN number. For real parts numbers, try ePER, but that'll be no help with ordering non OE parts.

 

[David C]

ePER shows three p/n for temperature sensors for Sei Sporting.
The one for the switch above, plus two others (one CF2 and the other CF3) which must be the ECU sensor.

A Google for 7588920 got a few results and most after-markets mention the OEM p/n in their listing, so it should help.

 

[Peerke]

ePER shows three p/n for temperature sensors for Sei Sporting.
The one for the switch above, plus two others (one CF2 and the other CF3) which must be the ECU sensor.

A Google for 7588920 got a few results and most after-markets mention the OEM p/n in their listing, so it should help.

David,

Many thanks for the effort, certainly very helpfull

Kind regards,

Peter

 

[cc1]

The part number for the sensor is 46477022. This not what you want, so if this number comes up in cross reference then avoid it.
My eper does not list anything for the switch for either a Cinq or Sei???.....
7588920 does not come up for use with the above cars either. It does list it for the many cars including the Punto 55/60/75/90 though.

 

[David C]

The part number for the sensor is 46477022. This not what you want, so if this number comes up in cross reference then avoid it.
My eper does not list anything for the switch for either a Cinq or Sei???.....
7588920 does not come up for use with the above cars either. It does list it for the many cars including the Punto 55/60/75/90 though.

7588920 comes up on my ePER for the Sei, I wouldn't have put it up if it didn't!!

46477022 is the ECU sensor for CF2 Sei & Cinq.
7588802 is the temperature gauge sensor for a Cinq. Which is the sensor he has, but is not what he wants.
Strangely it also lists 7588802 for an 899 Sei...

 

[cc1]

7588920 comes up on my ePER for the Sei, I wouldn't have put it up if it didn't!!

46477022 is the ECU sensor for CF2 Sei & Cinq.
7588802 is the temperature gauge sensor for a Cinq. Which is the sensor he has, but is not what he wants.
Strangely it also lists 7588802 for an 899 Sei...

My eper is V:60
I found 55188058 listed as a sensor for many models including Seicento MPI but I don't have a clue to It's use as 71719393 is the sensor complete with plastic housing for the intake manifold? Very confusing this version of eper.....

 

[David C]

My eper is V:60
I found 55188058 listed as a sensor for many models including Seicento MPI but I don't have a clue to It's use as 71719393 is the sensor complete with plastic housing for the intake manifold? Very confusing.

V60 is quite old.
I'm looking at V84 (May 2014)
It has 55188058 as the ECU sensor for an 1108 MPI Sei
No idea what 71719393 is, but it is MPI only.

Pic attached from ePER:

 

[cc1]

 

[David C]

Pic isn't working

 

[cc1]

Not just the sensor though.
When you look on e-bay, 55188058 fits hundreds of cars. Perhaps we need to have a parts cross reference for the FAQ's?