Brake Light Fault

[MoggieMorris]

Good evening Gents,

 

Im having a little bit of trouble with my '03 1.9 Galaxy.

I have had the same fault as many, of bulb failure light, no brake lights, flashing glow plug light and the implausable signal fault code, so i took the switch out to take a look at it. I tested it with a Fluke & found it to be working as it should, I also took it apart & cleaned it up, testing again afterwards to make sure I hadnt broken it. After fitting, I still have the same fault. 

Can anyone help with any pointers as to where I could be looking for the fault now if the switch is good?

Many thanks.

[smudger]

take connectors off switch connect together put ignition on do u have brake lights??

[BigDog]

Welcome.

Could be bulbs, switch or wiring. Seems unlikely to be all the bulbs. Lots of cars have broken wires inside the rubber gaiters near the tailgate hinges. Plenty of instructions on fixing, check the FAQ section.

If I recall correctly, there are actually 2 switches actuated by the brake pedal. One of them is for the cruise control (whether you have cruise or not, the switch is there) and is pressed last as the pedal rises. The other is for the brake lights. Have you been working on right switch?

Matt

[MoggieMorris]

Cheers guys,

 

Smudger - I will try that at work tomorrow.

 

BigDog - Im not entirely sure if it was the correct one, I could only see one up there, Ill take a look at that again tomorrow too. I presumed it was the right one as it was how it was described in the other posts about it. It had four pins, & the sprung plunger with the ratchet like end to it.

As the 4 pins, 2 contacts were normally open, 2 were normally closed (which closed/opened as the plunger was pressed), I presumed the normally open were for the brake lights to turn them on & the normally closed was for the cruise control to disengage it as u applied the brake?

[smudger]

moggie if brake lights come on wen u connect it definatly switch issue if they dnt then we come to that

[BigDog]

OK, sorry for switch confusion I am thinking of the wrong car.

Matt

[MoggieMorris]

Thanks guys, eventually got to link out the switch & found that to fix the problem.. Brake lights now work & the bulb failure warning light now is off :-D

The only thing is that the coil warning lamp still activates after a few seconds of starting the ignition... Is the fault code I had remembered in the Ecu? Will it need resetting b4 that stops?

[daddyfixit]

I would still be checking tailgate wires for this one .

[chrispb123456]

Thanks guys, eventually got to link out the switch & found that to fix the problem.. Brake lights now work & the bulb failure warning light now is off :-D

The only thing is that the coil warning lamp still activates after a few seconds of starting the ignition... Is the fault code I had remembered in the Ecu? Will it need resetting b4 that stops?

Are you saying the coil light comes on after switching on ignition or after starting engine

[MoggieMorris]

Sorry, to clarify, all I need to do is turn to position 2 with the keys, not start the engine,

Thanks.

[seatkid]

If you have linked out one the the two switches (its a dual device) then thats the reason the glow plug light comes on - the dual brake switch - basically one side controls the brake lights and the other sends a signal to the ECU for engine management purposes (inc cruise control cancellation amonst other things). Both sides go to the ECU for monitoring. If the two dont work together as expected, it throws a fault, flashing the glow plug light and you will lose some ECU management functions.

 

If the brake switch unit is bust, it needs to be replaced as a unit - it cant be frigged off......

[MoggieMorris]

The duel switch I have has 2 sets of contacts, 1set normally open circuit, 1set closed circuit. The way it works as far as I can tell, is that when the brake is pressed, the plunger raises up, swapping the contacts over... The way I tested is to link the brake contacts, therefore the switch would b in its brake applied state (ie the brake contacts are now closed circuit & the Ecu contact open circuit)

I don't see how the Ecu would see that as fault conditions?

[MoggieMorris]

Btw, a new switch has been ordered & is on its way :-)

[seatkid]

The two switches have four possible states - only two of which should ever occur. If you scan the ECU with VAGCOM/VCDS - you will see an error code - brake switch  "implausible signal" - which means an illegal combination was seen by the ECU.