Simon's new Xantia V6 and Leaf blog

[white exec]

Jim / Simon,

Looking at component 4010 (coolant level sensor), I can't make much sense of how it could work:
Pin 1 on it is permanent Gnd.
Pin 3 is +12v IGN, and same connection to pin 15 on 8010 (water temp control unit).
Pin 3 cannot be dragged down to a lower voltage by the sensor's electronics, because of its connection to IGN+.
?????
Does a pin 2 on the sensor appear on another diagram, maybe?

As circuited, this cannot operate the dash warning light.
Does it actually operate anything at all?
?????

How about other people's Xan S1's?

[xantia_v6]

Jim,

Can you scan the diagram for the S1 2.1TD which has the same header tank arrangement?

[xantia_v6]

How about other people's Xan S1's?

Mine (which may well have its original tank by the looks of it) has only 2 wires to the sensor:

[Mandrake]

The scan is greatly appreciated Jim, although it asks more questions than it answers!

Jim / Simon,

Looking at component 4010 (coolant level sensor), I can't make much sense of how it could work:
Pin 1 on it is permanent Gnd.
Pin 3 is +12v IGN, and same connection to pin 15 on 8010 (water temp control unit).
Pin 3 cannot be dragged down to a lower voltage by the sensor's electronics, because of its connection to IGN+.
?????
Does a pin 2 on the sensor appear on another diagram, maybe?

I don't think so, and besides, there is no pin 2 in the car, or wire... cable all looks original.

As circuited, this cannot operate the dash warning light.
Does it actually operate anything at all?
?????

How about other people's Xan S1's?

I agree - either there is an error in the circuit diagram about where pin 3 of the sensor goes to, or there is an error in the design of the car (a missing wire) that prevents this sensor from ever actually working. Take your pick!

If you compare with the S2 diagram I posted earlier you can see that it looks like pin 2 should go to pin 12 on the 8010 or pin 9 on the 004. (Same location)

So as far as I'm concerned, this sensor cannot possibly work the way it is hooked up, and Citroen really screwed up. Any S1 V6 owners willing to drain their coolant expansion bottle and test the warning light comes on while the engine is running - I'll bet you anything that yours doesn't work either...

If that is the case it should be possible to retrofit the missing wire, but where you would physically have to run it to splice into the run between the 8010 and the dashboard I'm not sure. Could be quite hard to find a good splice location.

I'm still a bit flummoxed by this whole thing. I know for sure the sensor in my S2 V6 worked as it lit on many occasions when the level got low - I never did pay attention to whether it had three wires or two but I'll bet it did have three.

Doesn't look like there is any point in buying a new sensor if it can't work as wired. There's probably nothing wrong with the sensor itself!

[white exec]

Agree with all that, Simon.
Bit worrying if all S1 Xantia's are the same!

If Jim has the S1 Instrument Cluster wiring diagram, this should show you where to connect to the warning light.

It's not just low level coolant that can trigger these sensors (into seeing 'no coolant' high resistance) - oil in water will do the same thing, from blown HG or heat-exchanger. I know all about the second thing. Twice.

[Mandrake]

It's probably easier to run a wire down the left wing to the Bitron (8010) under the left hand headlight than trying to get into the dashboard. Or if the wiring comes back from the Bitron in a convenient location near the expansion chamber do a solder and heat-shrink splice in the wiring loom. I'd need to check the cable routing diagram to see where it runs.

On the S2 V6 the coolant warning light is only triggered by a low coolant level, or via the Bitron if the coolant temperature is well past the high fan speed temperature. This is done via the brown sensor on the side of the block so disconnecting this will both put the fans on high and light the warning light. (I had a bad connection here recently and it was doing just that)

On the S1 V6 apparently only over temperature will trigger the light! But I can't see any reason why we can't run a wire from pin 2 of the sensor to the coolant warning light exactly like on a S2. A replacement 3 pin plug (since the pin is missing) and a bit of wire and heatshrink to do neat soldered joints should do the trick...

[white exec]

Possible cable route, to save battling with firewall, if you have to connect into the dash.
Have used this for a few extra cables on the XM:
http://www.club-xm.co.uk/forum/viewtopi ... 694#p64138

[Mandrake]

Possible cable route, to save battling with firewall, if you have to connect into the dash.
Have used this for a few extra cables on the XM:
http://www.club-xm.co.uk/forum/viewtopi ... 694#p64138

Can't follow your link as I'm not registered on that forum. Don't worry, I have no plans to do battle with the dashboard or firewall. If I did attempt such a modification I would run the wire towards the Bitron.

[white exec]

Go on . . . register! . . . whole new world out there! Ask Jim!

[Stickyfinger]

Mine is the same, two wires

[CitroJim]

I will scan up some more related diagrams in a bit.. Sorry for not doing it sooner but I've been away collecting and getting to know Gabriel

[Mandrake]

Mine is the same, two wires

But do we have a confirmed sighting of a S1 V6 low coolant warning light working yet though ?

How silly will we all feel if we discover the warning light has never worked from the factory....

[Stickyfinger]

Are we really saying Citroen would fit a sensor to one of the top of the range cars and install wires and bulbs in a system that does not work ?

[Mandrake]

Are we really saying Citroen would fit a sensor to one of the top of the range cars and install wires and bulbs in a system that does not work ?

Go on then - drain your coolant expansion bottle in the name of science and see if the warning light works! The suspense is killing me...

Yes it does seem to be a bizarre but inescapable conclusion. If the sensor only has a connection to power and ground, what can it do ? It's the same sensor part number as on the S2 as well, and on those pin 2 is the output of the sensor to the warning light...

The bulb does serve a purpose - it still shows coolant overheating, beyond the fast fan speed.

[Stickyfinger]

LOL.....unreal