Strange Brake Light Problem

[Uberderv 6]

Hi,

Noticed the other day that my drivers side brake light wasnt working, so I checked the bulb and it had blown. Changed the bulb and it still doesnt work, so tonight I have had the cluster out and cleaned all the connections also cleaned the plug to the cluster but its still not working

Just hoping someone might have any ideas

 

Ps the other side works fine.

[Mikey S 29 1 Cars]

Hi,

Noticed the other day that my drivers side brake light wasnt working, so I checked the bulb and it had blown. Changed the bulb and it still doesnt work, so tonight I have had the cluster out and cleaned all the connections also cleaned the plug to the cluster but its still not working

Just hoping someone might have any ideas

 

Ps the other side works fine.

 

 

its more than likely that the circuit board that the bulbs locate in is at fault. try a continuity test from the connector plug on the board to the pins that locate on the bulb itself. if its duff, you cant buy them separately, but theres always loads of complete lamps on ebay.

 

 

mike

[Uberderv 6]

Cheers for the reply,

Would it not be possible to resolder the board if thats the problem? I will test it today to see if thats the prob

[Cameron 16]

Got a multimeter?

If so, take both clusters out (10mm nut) and stick the brakes on with a bit of wood or something. Check for 12V at one of the pins in the large connector in the back of the NS cluster (the connector attached to the car loom) and that will be the pin for the brake lights. Then check for continuity between that pin and the pins in the other large connector (link loom to OS cluster). If you have continuity there then you know the NS cluster is fine, if you don't then unplug the connectors and clean up the pins with some sandpaper and try again.

 

Next check for continuity from the brake light pin to the connector on the OS cluster, it should be the same pin, for example if the NS brake light was pin 2, the OS will also be pin 2. If you have continuity here then the link loom is fine, if not clean the pins with sandpaper and try again.

 

If everything is fine so far, check for continuity from the brake light pin (on the NS cluster) to the spring terminal for the bulb - the terminal in the centre of the bulb hole - in the OS cluster. There's 2 terminals as its a dual filament bulb so make sure you check both. If you have continuity here then the OS cluster is fine, if not you have a broken circuit somewhere in the OS cluster that will need to be repaired.

 

If that's ok, check for continuity between the outer terminal of the bulb mounting hole (the metal ring) and the chassis earth. If you have continuity here then it can only be a dodgy bulb, if not you either have a broken circuit somewhere in the OS cluster or a dodgy earth that will need cleaning.

 

Hope that makes sense.

 

Ps, if you don't have a multimeter then I strongly recommend getting one and learning how to use it. Make sure you get a decent one too, there's little sense in cheaping out and getting the budget one. Gunson make a very good professional one that you can get from your local Halfords I think they're around £20.

Edited December 31, 2008 by Cameron

[Uberderv 6]

Cheers for all the info,

 

Just been out to get the multi meter but they had sold out of the one I wanted and only had the cheapo one left so I will try another store after new year

 

Got a multimeter?

If so, take both clusters out (10mm nut) and stick the brakes on with a bit of wood or something. Check for 12V at one of the pins in the large connector in the back of the NS cluster (the connector attached to the car loom) and that will be the pin for the brake lights. Then check for continuity between that pin and the pins in the other large connector (link loom to OS cluster). If you have continuity there then you know the NS cluster is fine, if you don't then unplug the connectors and clean up the pins with some sandpaper and try again.

 

Next check for continuity from the brake light pin to the connector on the OS cluster, it should be the same pin, for example if the NS brake light was pin 2, the OS will also be pin 2. If you have continuity here then the link loom is fine, if not clean the pins with sandpaper and try again.

 

If everything is fine so far, check for continuity from the brake light pin (on the NS cluster) to the spring terminal for the bulb - the terminal in the centre of the bulb hole - in the OS cluster. There's 2 terminals as its a dual filament bulb so make sure you check both. If you have continuity here then the OS cluster is fine, if not you have a broken circuit somewhere in the OS cluster that will need to be repaired.

 

If that's ok, check for continuity between the outer terminal of the bulb mounting hole (the metal ring) and the chassis earth. If you have continuity here then it can only be a dodgy bulb, if not you either have a broken circuit somewhere in the OS cluster or a dodgy earth that will need cleaning.

 

Hope that makes sense.

 

Ps, if you don't have a multimeter then I strongly recommend getting one and learning how to use it. Make sure you get a decent one too, there's little sense in cheaping out and getting the budget one. Gunson make a very good professional one that you can get from your local Halfords I think they're around £20.

[Cameron 16]

Cool, a cheap multimeter will do to get this problem sorted but its false economy as they are very limited on functions and quite unreliable.

[pug_ham 244 3 Cars]

Would it not be possible to resolder the board if thats the problem? I will test it today to see if thats the prob

You can take the whole of the rear liight apart but I doubt you'll be able to re-solder anything because its a metal bar & not a pcb arrangement inside the rear lights with any solderd joints.

 

I think it'll most likely be the bulb holder has some corrsion inside which is stopping it from working.

 

When you take the light unit off the car (10mm nut inside the aperture) there is another second 10mm nut which holds the bub reflector & holder / circuit board together. Undo this (with the bulbs out of the holder) & you can take it apart to get access to the insides as pictured below.

 

I found a big build up of black dust on one I had where the rear brake light used to work intermittently but since I 've cleaned that dust off its always worked fine.

 

Graham.

[Ricardo 0]

Pouring hot water over cluster from a freshly boiled kettle usually removes crud from bulbs and connections! Also breaks in the Circuit Board can be bridged with solder or bared wire soldered across.

[Uberderv 6]

Problem sorted

 

Took the light cluster out again and had a butchers at the back where the metal frame is, on closer inspection of the area with the problem you can see that it has been 'fiddled' with before at some point-

So I removed the plastic lugs which had been melted to keep it in position and the metal (which I think was Tin) was easily bent out of the way to reveal the problem below-

You cant see in the pic but beneath there is a thin stainless steel connector which the bottom of the bulb sits on. This the positive side of the electrical system as the earth is shared between all the lights and can easily be inspected. Anyway a layer of corrosion had built up between this and the upper tin frame breaking the connection.

I removed the lower connection and scraped off all the corrosion, I then bent the lower connector upwards slighty so it would connect with the upper part once it was bent back into position.

Due to the fact I had removed the plastic lugs which hold the upper section down I had to make a small hole through the metal and screw it into the plastic housing to keep it secure-

 

Main thing is it worked Thanks for all the help, next on the list is the fog lights ha ha ha

[Cameron 16]

Aha, not seen that before, good stuff.

[pug_ham 244 3 Cars]

Nice fix Pete, glad its sorted.

 

next on the list is the fog lights ha ha ha

Rear fog light or front driving lights?

 

If its the rear fog light then I'd suspect a corroded plug on the light behind the rear valance as they seem to suffer quite badly from this but it could also be a broken wire to that plug. I had this on mine so I replaced both wires into the plug.

 

Let me know if you need some wire & connectors to fit into the plug.

 

Graham.

[Uberderv 6]

Nice fix Pete, glad its sorted.

 

 

Rear fog light or front driving lights?

 

If its the rear fog light then I'd suspect a corroded plug on the light behind the rear valance as they seem to suffer quite badly from this but it could also be a broken wire to that plug. I had this on mine so I replaced both wires into the plug.

 

Let me know if you need some wire & connectors to fit into the plug.

 

Graham.

 

Cheers, Both dont work I have tried it with the head lights on but the front only come on when its on full beam, the back one doesnt seem to work at all

[jackherer 543]

Cheers, Both dont work I have tried it with the head lights on but the front only come on when its on full beam, the back one doesnt seem to work at all

 

The fronts are driving lights, they are supposed to come on with the main beam only.

 

The rear is usually down to corroded connections as it is so exposed.

[pug_ham 244 3 Cars]

The fronts are driving lights, they are supposed to come on with the main beam only.

The fronts on the D turbo 205 can actually be front fogs as they were a dealer fitted option afaik & not the same as the driving lights fitted to the GTi / STDT.

I've seen one or two five door D turbo's in my local scrapyard & they both had a seperate blue switch (& the five hole surround) on the dash for the front fogs.

 

Has your car got this Pete or just three dash mounted switches? (Hazards, heated rear window & rear fog). If not then they only work like Kieran states as driving lights with full beam only.

 

Probable they have the same thing causing them not to work, corroded wires & connectors.

 

Graham.

[jackherer 543]

The fronts on the D turbo 205 can actually be front fogs

 

I didn't realise it wasn't a GTI, the username 'Uberderv' was a clue I suppose

[Uberderv 6]

Cheers for the advice chaps Dont mind about the front as I dont use them anyway but I will check the connections out on the rear valance.

 

 

Graham my car only has the three switches on the dash which only work when they want aswell LOL

 

Was going to get a GTI but this one came up and if perfic for my needs at the moment