Thread: 300tdi oil pressure warning light

there is a connector up at the instrument cluster unit.
Oil pressure light runs off the White with brown tracer.

Looking at the wiring diagram, the wires from the sender all the way to the warning light is white/brown all the way(sounds obvious, but not always so!)

That was exactly what I was after, thanks, I'm hoping to just run a new wire from the new pressure sensor to the instruments and it magically work, here's hoping!

Originally Posted by finallyrangie

That was exactly what I was after, thanks, I'm hoping to just run a new wire from the new pressure sensor to the instruments and it magically work, here's hoping!

Just be aware that the light does not work from the same type of pressure sensor as your additional pressure gauge. The original light is just a simple lamp that is activated by the original pressure SWITCH, which completes a circuit to earth when there is no oil pressure. ie: it opens on a rise of oil pressure.

Your additional electrical driven gauge uses a variable voltage provided by the "sensor", not an on-off contact.

Originally Posted by Old Farang

Just be aware that the light does not work from the same type of pressure sensor as your additional pressure gauge. The original light is just a simple lamp that is activated by the original pressure SWITCH, which completes a circuit to earth when there is no oil pressure. ie: it opens on a rise of oil pressure.

Your additional electrical driven gauge uses a variable voltage provided by the "sensor", not an on-off contact.

Thanks, I've fitted a T piece and have an original pressure sensor on the other side, so I'm running two sensors, so hoping I can run the wire from the factory sensor back to the instruments and, possible with a new lamp, have a dash light as well as the gauge, hope that makes sense.

Originally Posted by finallyrangie

Thanks, I've fitted a T piece and have an original pressure sensor on the other side, so I'm running two sensors, so hoping I can run the wire from the factory sensor back to the instruments and, possible with a new lamp, have a dash light as well as the gauge, hope that makes sense.

Yes that is good, BUT the original light needs 12 volts and I do not know if that connection on the back of the binnacle outputs 12 volts, or the switch is fed from someplace else. If you have a test meter you could check it with the ignition turned on before you connect it up.

Originally Posted by Old Farang

Yes that is good, BUT the original light needs 12 volts and I do not know if that connection on the back of the binnacle outputs 12 volts, or the switch is fed from someplace else. If you have a test meter you could check it with the ignition turned on before you connect it up.

The "output" on the back of the binnacle should actually be an input from the sensor and the input is an earth signal.

Originally Posted by BathurstTom

The "output" on the back of the binnacle should actually be an input from the sensor and the input is an earth signal.

On all the various ones that I have worked on the oil pressure switch (sensor) provides the earth. That is why some people get into trouble when they wrap sealing tape around the threads. It can no longer earth.

I'm hoping, all things being equal, that I can get away with reconnecting the sensor to the instruments, and hopefully the binnacle completes the circuit.

Lots of hoping going on, I'm going to try and get time over the weekend to have a go and we shall see what we see.

I will let you all know what happens, if it's not easy I will be sobbing whilst I type!