Fuel Gauge not working, but Low Fuel Light does work ?

[pete12345]

As per the topic title, the fuel gauge does not work on our 2004 Dispatch Van.

Strangely the Low Fuel light does work when the tank gets low. My brother keeps a gallon can in the van just in case, but so far he fills up when the light comes on & gets at least £100 in the tank.

The light working does imply the sender is working, but we are not sure. Assuming the sender is just the usual resistance type, is the light done by the electronics based on voltage or resistance ?

My iCarsoft Max doesn't seem the read the sender value, so we probably need to check the resistance before dropping the tank & testing the sender.

Any ideas welcome,
Pete

[mickthemaverick]

You may find some general clues in the video linked below while you wait for a Despatch owning member to answer the queries about the light

https://tooltrip.com/how-to-check-fuel- ... unit-ohms/

[pete12345]

Yes the plan is to find the wires & measure any voltage on them. Not sure if one side is 12V, 5V or ground, but based on other citroen stuff I have seen, one side should be an analog ground from the BSI. Shouldn't be too hard to probe through the insulation & see what we get.

I'm also planning to see if my DS150E will show anything.

[xantia_v6]

According to the wiring diagram that I have, there is no separate sense wire for the low fuel warning light, it is derived from the gauge sensor by electronics in the instrument cluster. That would seem to indicate that the fault is in your instrument cluster. I presume that you are aware of the dangers of replacing the cluster with one from a vehicle with higher mileage?

[pete12345]

Yes, same issue if I needed to change the cluster in my old 1998 Range Rover, and probably lots of vehicles these days.

Wondering if there might simply be a dry joint in the cluster ? Does anyone know if the BSI to Cluster signals are separate, or a data stream ?

[xantia_v6]

The fuel gauge is entirely analog and does not go via the BSI. It could be a faulty joint on the PCB, or the gauge unit itself.

[pete12345]

ok, thanks. The diagrams I looked at must be for a different model or year. Can you help with correct wiring diagram ?

Ours is a 2004 1.9 Diesel. VIN = VF7**************[VIN obfuscated, can be read by forum staff]

[xantia_v6]

I think that this is correct for 2004.

[pete12345]

I think that this is correct for 2004.

Thanks for the diagram. Do you happen to know the wire colours & what connector(s) I need to look for ?

Not sure about French colour designation. Don't speak French !!

Pete

[PaulC5]

This is from a Haynes manual for a C5
BA white
BE blue
BG beige
GR grey
JN yellow
MR brown
NR black
OR orange
RG red
RS pink
VE green
VI mauve
VJ green / yellow