View Full Version : Hand brake switch

05-02-04, 10:40 AM
Please can anybody tell me on a mark 3 sumo which wire/wires should be connected to the handbrake switch and warning light as I am getting very p*ssed of at blowing fuses.
Also which wires is it on the low level brake fluid switch sould be connected.

Any help much appreciated.

05-02-04, 11:20 AM

The Sumo loom does not come supplied with a wire for the handbrake (at least mine didn't - not sure if it has changed since).

If you want to fit one, run a live wire onto one side of your warning lamp, and run another wire to the handbrake switch (acts as an earth). When the handbrake is on it will earth via the switch and your lamp should come on.

As for the low level brake fluid, if I recall correctly, this is black w/white stripe. To test this, connect it up and press the centre of the lid that fits onto the brake fluid reservoir. If you've wired it in correctly, the lamp should come on (learned that one at the SVA centre!).

Tony B

07-02-04, 06:11 PM
Hi Mat,

Tony's info is correct re the fluid level warning light, it is white stripe on black but a second wire is also needed to complete the circuit which is plain black. Both emerge from the loom adjacent to the master cylinder so should be easy to spot.

08-02-04, 12:31 AM
Thanks I will try it out next week and let you know how I go on.


30-01-05, 10:52 AM
Hi chaps, the brake fluid switch on mine has 3 wires 1)Brown (earth), 2)brown/green - goes to handbrake switch (on Sierra), 3) Brown/yellow - goes to lamp (on sierra).
I've connected the earth ok, but which one (of 2 & 3 above) do I connect the black/white wire to ?

TIA, Rich

Ian Lloyd
31-01-05, 05:25 PM
My loom does have a hand brake wire in it. cannot remember the colur (would have to go to the garage) but it emerges from the dash board bundle of wires it is extra long compared to the others and is a single wire

01-02-05, 09:14 AM
wire to handbrake switch is black/white

01-02-05, 06:35 PM
I have the wire to and can also confirm its black/white, phew thought I had another thing to do before sending her off to paint. Its funny everytime I think I finish my to do list before paint I keep finding something else. The thing is I want to minimise the amount of leaning on a 3K imperial blue suit.

Sorry if offend anyone but yes I think Imperial blue is my choice. I have two weeks though and will probably change my mind 100 times again yet


Marty V6
01-02-05, 06:45 PM
Can anyone throw any more light on the brake test whatsit in the lid of the master cylinder. I cant seem to find any wires in the loom - knowing my luck the original builder cut them off..

I want to wire this up, and have got the brake warning light. I have no wires from the lid of the master cylinder, just the electrical connector which is part of the lid.

Can anyone tell me how to wire this, and is it also connected in with the handbrake switch which I think shares the same warning light - could be wrong on that too.



Ian Lloyd
02-02-05, 04:05 PM

There are 2 wires on my loom to the master cylinder switch a black /white and a black.

Black goes to earth, the black/white comes from the warning light which has a power supply to the other side, the handbrake switch is also black/white wire and is connected in parrallel to the master cylinder switch. The effect is that both master cylinder and handbrake switch earth the circuit and hence illuminate the warning light.

Marty V6
02-02-05, 07:02 PM
I forgot to say in my previous posting that my mk3 sumo has a mk2 loom i.e. it is only a 6 fuse loom - strange but true. As such I have no wiring in the loom for either the handbrake or low brake fluid level warning circuits and these are not drawn in the wiring diagram either. So I will have to make the circuits up from scratch.

Car is registered 1999 so didnt need to qualify for SVA. I just fancied including these in the car.

The low fluid connector on the reservoir cap has three pins but two seem to be siamesed. Not sure how to proceed.