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Brake Warning wiring

Posted: Sun Feb 17, 2019 8:51 am
by bobsmate1001
Where does the wiring circuit get its power from.
I know I have power into the back of the warning light cluster but I don't have power anywhere else.
Nothing at the handbrake switch and nothing at either of the brake pad warning ends.
Anyone got any clues?

Brake Warning wiring

Posted: Sun Feb 17, 2019 9:10 am
by scimjim
The brake warning circuit provides the earth path.

Live is supplied to one side of the bulb(s) which is earthed if the pads wear down, the handbrake is applied or low fluid/low pressure (depending on model).

Brake Warning wiring

Posted: Sun Feb 17, 2019 12:55 pm
by bobsmate1001
Thats my understanding too but neither are working even when I earth then seperately!

Brake Warning wiring

Posted: Sun Feb 17, 2019 1:02 pm
by TrevorG
Apologies for this, but it's a personal viewpoint.

Cut the wiring off, it's a pain anyway! Pads without the wiring link are cheaper and you can get a better choice of pads. If people can't be bothered to regularly check their brake pads, then......!*!

Brake Warning wiring

Posted: Sun Feb 17, 2019 3:52 pm
by bobsmate1001
Already done that as part of the brake upgrade, wired a low fluid warning using the driver side pad wiring but still get no light when the handbrake is pulled.
Is there an inline fuse I am missing somewhere?

Brake Warning wiring

Posted: Sun Feb 17, 2019 3:53 pm
by bobsmate1001
I would have thought I should find some voltage at the handbrake switch no?

Brake Warning wiring

Posted: Sun Feb 17, 2019 5:05 pm
by scimjim
No. What model car is it? On the Small sports you have to join the two black/white wires that go to the pad sensors if you snip it off. There’s no need to cut the wires, with them simply disconnected the other systems will work fine.

Brake Warning wiring

Posted: Sun Feb 17, 2019 9:11 pm
by bobsmate1001
Its an SE6 A or B not sure.
Both pad sensors disconnected but still I get nothing!

Brake Warning wiring

Posted: Sun Feb 17, 2019 9:14 pm
by scimjim
On a GTE it’s usually the switch at the base of the handbrake not making a good earth.

Does the light illuminate with the low level switch pushed down?

Edit, sorry - you said neither are working. Presumably bulb is good and you have live to one side, so if the handbrake switches and the low level warning ARE making a good earth, there’s a break in the wiring somewhere.

Brake Warning wiring

Posted: Sun Feb 17, 2019 11:21 pm
by TrevorG
Sorry, didn't realise it's the handbrake and fluid only connected now. Recently done mine and found that when someone liberally squirted white grease onto the handbrake cable from under the car, it had gone up into the two switches and was acting as a barrier to the connection. I undid the switches, cleaned out and bent the copper connector slightly to give a stronger connection when the handbrake is on. All then worked.

Another silly point.....you say you've got power at the back of the light cluster. Have you tested the brake warning lights in said when earth is supplied? Grandmother and eggs thing again!

Brake Warning wiring

Posted: Mon Feb 18, 2019 7:19 pm
by bobsmate1001
I am game for anything at the moment to get a result, I assume I have power to the cluster as the low fuel warning light comes on and it comes from the same feed, I have even replaced the cluster.
I will try cleaning the switches, I know the handbrake is a good earth because I have used it when testing other circuits