Piggy back water in fuel sensor off existing one

[Gavx Junior Member Find all posts View Profile Close Gavx]

I am installing a Water watch (http://www.waterindiesel.com.au/6308/) which sits in the fuel line before the filter and whose purpose is to sense water and report it to a warning light.

In its stock form the water sensor receives power, earth and has an output signal wire which in turn is wired to a relay, warning light and buzzer. Presumably the purpose of the relay is to provide power to the light and buzzer.

When installed as per the instructions when the ignition is activated the sensor receives power and runs a self test, providing power to the relay and therefore the light and buzzer. After 8 seconds the light and buzzer switches off.

I do not like this wiring set up. I prefer to wire the sensor into the existing water in fuel circuit/warning light so that if either the factory provided water in fuel sensor or the Water Watch sensor are activated just the one dashboard light goes on.

Can someone help me with some questions.

1. Does the sensor or the relay control the timing of the self test? I think the sensor as I suspect timer relays are special and this relay looks bog standard.
2. Can I assume the systems all run on 12 volts including the dashboard light?

My plan is to get power for the Water Watch sensor from one side of the factory water in fuel sensor. The output signal from the Water Watch connects to the other wire of the factory sensor. The Water Watch also needs an earth, which I can just get from the body. So if either sensor activates the one light illuminates. I should add the factory sensor just has 2 wires.

Does this seem like it would work? In other words can I wire the 2 sensors together in this manner (parallel I think) to activate a common warning light? Or does this method half the power or develop some sort of feedback to each sensor…or something.
Hope this is clear.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

The service manual shows the sedimentary sensor as a switch with a resistor in series,
also I think there is a sensor in the filter for detecting when the filter is clogged but
can't find a mention of it in the meter schematics?

Should be possible but you'll need to do some research, also light and buzzer is probably better
as you'll notice them but may miss the light only, or does the dash lamp have a buzzer too?

[Gavx Junior Member Find all posts View Profile Close Gavx]

Does the presence of the resistor suggest that the dashboard light does not work on 12 v but something less?

[adrian5800 Advanced Member Find all posts View Profile Close adrian5800]

The 1KZ's have a buzzer and the dash warning lamp but I'm not sure the 1KD's do. I would be surprised if they didn't.
I added a sensor to my water trap and connected it to the original dash lamp/buzzer. I had to use a transistor and relay for the sensor I added because it is just a stainless probe which relies on path to earth through the water which collects in the trap. There isn't enough PD and resulting current to trigger a relay alone, so the transistor merely amplifies the current to trigger the relay.
I can give you details of the wiring and parts I used to make this work. I also configured a 2-3 sec self test when the ignition is turned on.

Ades

[Gavx Junior Member Find all posts View Profile Close Gavx]

I don't think the KDJ has a buzzer.
Looking at the factory sensor it just looks like a float type mechanism. I will look at this in greater detail tomorrow.