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Front Lights On When I Brake


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#1 Blink

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Posted 17 May 2010 - 08:22 PM

Hi sorry if this has been posted before, I think this may be a common problem according to search engine results, but fixing it is driving me mad!

Driving home I noticed in the reflection of the car in front when I applied the brakes, dim lights were coming on, now its a bit darker I can now also see the dashboard lights are coming on under braking too. When I turn my side or headlights on my brake lights are on permenantly....unless I open the tail gate then the problem goes away? My reg plate lights are now not working either, cant seem to see if they have a separate fuse?
Brake light bulbs look ok both doulble filament and it seems impossible to put them in the wrong way round.

Any help on this is greatly appreciated.


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#2 stef123

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Posted 17 May 2010 - 09:51 PM

Hi sorry if this has been posted before, I think this may be a common problem according to search engine results, but fixing it is driving me mad!

Driving home I noticed in the reflection of the car in front when I applied the brakes, dim lights were coming on, now its a bit darker I can now also see the dashboard lights are coming on under braking too. When I turn my side or headlights on my brake lights are on permenantly....unless I open the tail gate then the problem goes away? My reg plate lights are now not working either, cant seem to see if they have a separate fuse?
Brake light bulbs look ok both doulble filament and it seems impossible to put them in the wrong way round.

Any help on this is greatly appreciated.


i would put money on it being a bad earth connection somewhere

#3 Blink

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Posted 18 May 2010 - 09:15 AM

i would put money on it being a bad earth connection somewhere

Thanks for the reply, any usual suspects (bad earth) to look out for?

#4 hawker

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Posted 18 May 2010 - 10:39 AM

I would start with disconnecting the battery and cleaning the terminals along with the earth line that runs off the negative terminal onto the bodywork. This is quite a common "bad earth" point that can corrode and/or get badly contaminated.

#5 Blink

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Posted 18 May 2010 - 12:47 PM

I would start with disconnecting the battery and cleaning the terminals along with the earth line that runs off the negative terminal onto the bodywork. This is quite a common "bad earth" point that can corrode and/or get badly contaminated.


Those look ok, checked fuses & bulbs, now when i brake rear side lights not brake lights are coming on, I hate electrics! What am I missing?

#6 Blink

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Posted 18 May 2010 - 01:43 PM

Those look ok, checked fuses & bulbs, now when i brake rear side lights not brake lights are coming on, when I turn side\headlights on nothing is coming on at the rear, I hate electrical problems!

Found a severed wire, top right of enginge bay, disappears under the plastic whch covers wiper motors...I assume, anyway repaired it but has made no difference so not sure what that did?

#7 Dan62

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Posted 18 May 2010 - 02:06 PM

The bad earth (if it is that) will be at the point common to the brake / tail lights to cause this problem, i.e at the bulb socket. If its not a bad earth the next likely suspect is one of the rear brake / tail bulbs itself, the filaments may have shorted.
Take the bulbs out, one of them should be causing the additional lights to come on.

#8 Blink

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Posted 18 May 2010 - 03:27 PM

Bit of an update..... Have replaced both stop\tail lights and licence plate light units which are still not working. Smoke has started to appear through the back of the steering wheel cowling! I turned car off, removed the lower plastic so I could see the pedals and wiring, the wires from the brake plunger (for want of a better term) become extremely hot when brake pedal is pressed (I know it is because there is current going through but seems excessive)I think it may be melting wires hence the smoke? now I dont know what to do.....

#9 stef123

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Posted 18 May 2010 - 05:50 PM

Bit of an update..... Have replaced both stop\tail lights and licence plate light units which are still not working. Smoke has started to appear through the back of the steering wheel cowling! I turned car off, removed the lower plastic so I could see the pedals and wiring, the wires from the brake plunger (for want of a better term) become extremely hot when brake pedal is pressed (I know it is because there is current going through but seems excessive)I think it may be melting wires hence the smoke? now I dont know what to do.....


sounds like a short circuit in the system somewhere. it might be time to speak with a professional auto spark now before this gets very expensive or possibly causes a fire

#10 Blink

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Posted 18 May 2010 - 08:43 PM

sounds like a short circuit in the system somewhere. it might be time to speak with a professional auto spark now before this gets very expensive or possibly causes a fire


You're right but funds is the problem....the car is not being used until sorted.
I feel the reg plate lights not working is no coincidence having fitted brand new ones today with no affect, will be tracing as much wiring as I can tomorrow. I just hope that the damage hasn't already been done. If anyone has any other input or ideas to check or try please post


#11 rog99

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Posted 19 May 2010 - 09:46 AM

I would try to isolate which circuit the fault is on.

You could pull the brake light Fuse 54 in the central fuse box behind the glove box.
Then check if the other lights work.

If the fault is still there try putting this back in and pull the side lights Fuse 22 in the engine compartment box and try again.


Have you tried the high level brake light? try disconnecting this and see what happens.

I would have thought that as the brake light circuit is taking too much current Fuse 54 would have blown.
You might consider putting a lower rated fuse than the 15A in here until you find the fault.

I have an estate and there is a multi-block connector above the nearside rear wheel arch but I don't know where this is on the hatchback. This could have had water ingress.

Roger

#12 Blink

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Posted 19 May 2010 - 10:28 AM

I would try to isolate which circuit the fault is on.

You could pull the brake light Fuse 54 in the central fuse box behind the glove box.
Then check if the other lights work.

If the fault is still there try putting this back in and pull the side lights Fuse 22 in the engine compartment box and try again.


Have you tried the high level brake light? try disconnecting this and see what happens.

I would have thought that as the brake light circuit is taking too much current Fuse 54 would have blown.
You might consider putting a lower rated fuse than the 15A in here until you find the fault.

I have an estate and there is a multi-block connector above the nearside rear wheel arch but I don't know where this is on the hatchback. This could have had water ingress.

Roger


Morning Roger
Thanks for post, I too have an estate......minus a lot of interior trim as I check the length of the car, will try your suggestions mate let you know how I get on.

When I bought the car the brake light fuse had blown, put another in and all seemed ok till now? Mechanics im fine but when it comes to electrics im a bit of a simpleton so fail to understand what the symptoms are telling me.


#13 Blink

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Posted 19 May 2010 - 11:34 AM

On inspection of fuse 54 (Brakes) the plastic surround looks as though it has melted a little but for some reason the fuse has not blown? With the fuse removed turned on side lights still nothing at rear, fuses for these seem ok?
Also found fuse 32 (light switch) had a 20 amp instead of a 10 and this had blown, replaced but no difference.

#14 rog99

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Posted 19 May 2010 - 12:01 PM

Sorry - where I got fuse 22 for the side lights I don't know!.
Fuse 47 [lhs] and Fuse 48 [rhs] in the central fuse box are the side light fuses.

These supply both back and front side lights so is it just the back ones not working?

#15 Blink

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Posted 19 May 2010 - 12:15 PM

Sorry - where I got fuse 22 for the side lights I don't know!.
Fuse 47 [lhs] and Fuse 48 [rhs] in the central fuse box are the side light fuses.

These supply both back and front side lights so is it just the back ones not working?


Lol, did wonder about fuse 22, did work out the right ones though.
you're correct, front sidelight work, rears dont?

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