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Brake fluid level switches
Lightning - 11/12/03 at 02:22 PM

I have just got 2 Fiesta brake level float switches for my bias bar brakes.
Why 3 wires in each what do they do?
Earth , feed and light ?

Can someone save me some time and tell me....Thanks

JoelP - 11/12/03 at 04:57 PM

IIRC from my wiring diagram, you have a feed, one to the brake light, and also one to the handbrake to operate the test function. it earths thru the handbrake switch, or thru the terminal with the single wire on in. HTH...

Lightning - 11/12/03 at 07:15 PM

I dont have a handbrake switch. Do you know if you need a test function for the SVA. Would a seperate switch do? if so does it just go to earth?

JoelP - 11/12/03 at 07:19 PM

yeah, modern cars just have it on the handbrake for simplicity, but it is an SVA requirement that the brake fluid sensor can be tested. a separate switch should do the trick!
basically, the live from a fuse goes into the dash bulb, then into one side of the float sensor. A wire from the same side then goes to the test switch (so that it can be activated/earthed with out the float having to drop) and the other side of the float switch also goes to earth, so that the warning light can be activated by either earth route.

Lightning - 11/12/03 at 07:49 PM

Well I thank you very much. That is all clear so off to the garage.

I shall wire up the bulb and then to each float in parallel so that if either of the floats drop it will set the light off.

It just means that the test swith will also have to go behind the steering wheel with all the other junk that i can be bothered to make SVA complient.

Findlay234 - 12/12/03 at 09:17 AM

what does it mean to "test" a brake fluid switch?

stephen_gusterson - 12/12/03 at 10:09 AM

I think its that SVA want to see that there is an indication that the bulb has failed.

Most production cars have the fluid light also to the handbrake. So, when you start the car, red lamp is on - if it isnt you will notice. taking the handbrake off puts the light out.

If it stays on, its cos the fluid switch is on and supplying the light.

Some older cars had a little push button dimple thingy on the reservoir cap that you press down to make the switch - waste of time cos its a two man job - yer cant see the dash lamp!

atb

steve

[Edited on 12/12/03 by stephen_gusterson]