Board logo

Low brake fluid warning wiring
speedyxjs - 24/12/09 at 07:39 PM

Iv wired my brake fluid warning but its working the wrong way. Im getting the light on when the fluid is normal and the light goes off when it is low. What have i done wrong?

flak monkey - 24/12/09 at 07:45 PM

See if you can figure it out from this:




Treat the durite switch as 2 seperate items, the handbrake switch and the warning light.

austin man - 24/12/09 at 07:46 PM

how is it wired at the moment this will help. Is the live going through the bulb first or through the switch on the master cylinder?

speedyxjs - 24/12/09 at 07:51 PM

This is how it is currently wired: Rescued attachment BWL.JPG
Rescued attachment BWL.JPG

ReMan - 24/12/09 at 07:59 PM

I'd say nothing, but the switch in the m/c is the wrong way round/wrong terminals for it to work

speedyxjs - 24/12/09 at 08:01 PM

quote:
Originally posted by ReMan
I'd say nothing, but the switch in the m/c is the wrong way round/wrong terminals for it to work


I was afraid someone might say that

Is there any way to get round this (ie make the light come on when there is no current)?

austin man - 24/12/09 at 08:02 PM

Electrical isnt my strong point but shouldnt the power from the switch feed go to the switch then to the bulb? a live feed to the bulb and an earth will light the bulb regardless as the supply isnt switched before the bulb other than direct switching from the ignition looking at your drawing.
I could be totally wrong

speedyxjs - 24/12/09 at 08:09 PM

quote:
Originally posted by austin man
Electrical isnt my strong point but shouldnt the power from the switch feed go to the switch then to the bulb?


It does go to the switch and then to the bulb.

[Edited on 24-12-09 by speedyxjs]

omega 24 v6 - 24/12/09 at 08:24 PM

quote:

Is there any way to get round this (ie make the light come on when there is no current)?


Yes you could use a change over elay but then you would have an energised relay on all the time. If you used ign feeds for the dash and m/c switch then it'd stop the battery going flat because of this. Not an ideal solution but it'll get you by.

Chippy - 25/12/09 at 12:17 AM

If you had a hand brake warning light the switch just earths the lamp, putting the lamp on, (so lamp is live all the time), what you have got to do is treat your fluid switch the same, it has to earth the lamp. Hope that all makes sense. Cheers Ray

Feankengeep - 25/12/09 at 01:27 PM

Hi speedy,

You need a change over relay (5 pin) and a base from the likes of Maplins, much cheapness.
Wire the relay coil 85 annd 86 using the wires that currently connect to the lamp so that the coil energises as long as ignition is on or engine is running and fluid level is correct.
Then use relay connections 30 and 87a to switch your dash lamp.
So, the lamp lights if the relay does not get a supply from the switch, therefor reversing the operation of the fluid switch.

Boyd


PS be sure to not to use permanent +ve for any of the above, only ign supplies.

[Edited on 25/12/09 by Feankengeep]

omega 24 v6 - 25/12/09 at 03:46 PM

quote:

Hi speedy, You need a change over relay (5 pin) and a base from the likes of Maplins, much cheapness. Wire the relay coil 85 annd 86 using the wires that currently connect to the lamp so that the coil energises as long as ignition is on or engine is running and fluid level is correct. Then use relay connections 30 and 87a to switch your dash lamp. So, the lamp lights if the relay does not get a supply from the switch, therefor reversing the operation of the fluid switch. Boyd PS be sure to not to use permanent +ve for any of the above, only ign supplies.



Yep what he/I said.

Or just change things around and make it right as others have said. Get a meter and suss out how to work it and you'll be able to work things out for yourself in the future. the whole car building experience should be treqted as a learning experience IMHO.