jackrory Posted February 20, 2007 Report Share Posted February 20, 2007 my right side brake light went 3 weeks ago..no probs car was booked into audi for some warranty work that week so ill get em to change it..they did..it blew again yesterday..what is going on with this light twice in the space of 3 weeks.. Quote Link to comment Share on other sites More sharing options...
Will22 Posted February 20, 2007 Report Share Posted February 20, 2007 Change both sides, same with side lights Quote Link to comment Share on other sites More sharing options...
SPLiiX Posted February 20, 2007 Report Share Posted February 20, 2007 But they run off a different fuse - so why change both sides?? Quote Link to comment Share on other sites More sharing options...
S4teve Posted February 20, 2007 Report Share Posted February 20, 2007 This may just be bad luck or you may have a problem such as a loose connection (this would increase resistance and current flowing through the circuit and second to the fuse the bulb is the weakest point) It is unlikely a power surge is causing this problem but blown bulbs is a common symptom - it would be strange especially to pick on the same bulb twice. Change it once more to see for certain if there is a recurring problem Quote Link to comment Share on other sites More sharing options...
SPLiiX Posted February 20, 2007 Report Share Posted February 20, 2007 And don't touch the bulb with your fingers! Quote Link to comment Share on other sites More sharing options...
Will22 Posted February 20, 2007 Report Share Posted February 20, 2007 [ QUOTE ] And don't touch the bulb with your fingers! [/ QUOTE ] Why? It's been known for years that on all vag car you change both sides. The worst ones are the Mk4 Golf Quote Link to comment Share on other sites More sharing options...
S4teve Posted February 20, 2007 Report Share Posted February 20, 2007 The theory goes.............. if you touch a glass light bulb with your bare fingers you will leave oils (from your skin) on the glass which when heated will burn and cause premature failure of the bulb. This is certainly true of all high temp lighting such as halogen and applies in motor and domestic situations. I shouldn't worry about side light, brake light etc - they do not get hot enough. Quote Link to comment Share on other sites More sharing options...
Will22 Posted February 20, 2007 Report Share Posted February 20, 2007 I knew about not tuching the glass of the halogen blubs but never thought about the side/brake lights and so on, cheers Quote Link to comment Share on other sites More sharing options...
danksy Posted February 20, 2007 Report Share Posted February 20, 2007 [ QUOTE ] [ QUOTE ] And don't touch the bulb with your fingers! [/ QUOTE ] Why? It's been known for years that on all vag car you change both sides. The worst ones are the Mk4 Golf [/ QUOTE ] You mean change both sides simultaneously? Whats the reasoning for this? Quote Link to comment Share on other sites More sharing options...
Will22 Posted February 20, 2007 Report Share Posted February 20, 2007 Yes both sides at the same time, as for the reasoning for this, I don't know but it works. It's something to do with the current that the new bulb uses or something like that. It was years ago that I was told this Quote Link to comment Share on other sites More sharing options...
P_G Posted February 21, 2007 Report Share Posted February 21, 2007 I've just changed one rear bulb last week but only the one; will do a little experiment to see how long it lasts having not changed both rear bulbs at the same time. I see what you are getting at Will, somrthing along the lines of uneven impedance means increased electrical wear rate, however this might only be true of higher volt system, 12v and above. the rear lights are only 5v so I don't know whether that will make any significant difference. Will soon find out though! Quote Link to comment Share on other sites More sharing options...
jackrory Posted February 21, 2007 Author Report Share Posted February 21, 2007 thanks...i do have a spare bulb so i'll give it a go..anyone else find it a pain to remove the light cluster on a b6 avant.. Quote Link to comment Share on other sites More sharing options...
P_G Posted February 21, 2007 Report Share Posted February 21, 2007 IIRC the B6 saloon and avant ones are just one screw and Bob's your auntie?! Quote Link to comment Share on other sites More sharing options...
jackrory Posted February 21, 2007 Author Report Share Posted February 21, 2007 i had to change the left bulb over christmas..after i got the screw out the actual light cluster took me ages to get off..is there a nak to it.. Quote Link to comment Share on other sites More sharing options...
PetrolDave Posted February 21, 2007 Report Share Posted February 21, 2007 [ QUOTE ] the rear lights are only 5v [/ QUOTE ] All the bulbs are 12V, but with different wattage ratings (brightness) 5W and 21W being the most common. Quote Link to comment Share on other sites More sharing options...
P_G Posted February 21, 2007 Report Share Posted February 21, 2007 Sorry Dave, got my W and V the wrong way round! Quote Link to comment Share on other sites More sharing options...
UBM Posted February 21, 2007 Report Share Posted February 21, 2007 And impedance is not a correct term - how the feck can a bit of grease interfere with the voltage and current? I think you'll find that the problem is due to the non-uniform heating of the higher wattage bulbs, such as a 55w halaogen headlamp bulb. The grease acts as a heat sink and the glass of the bulb expands at different rates..... Quote Link to comment Share on other sites More sharing options...
S4teve Posted February 21, 2007 Report Share Posted February 21, 2007 [ QUOTE ] how the feck can a bit of grease interfere with the voltage and current? [/ QUOTE ] Not sure there was a suggestion of this ? You are correct in your statement about the grease acting on the lamp glass when heated [ QUOTE ] I think you'll find that the problem is due to the non-uniform heating of the higher wattage bulbs, such as a 55w halaogen headlamp bulb. The grease acts as a heat sink and the glass of the bulb expands at different rates..... [/ QUOTE ] Quote Link to comment Share on other sites More sharing options...
UBM Posted February 21, 2007 Report Share Posted February 21, 2007 [ QUOTE ] [ QUOTE ] how the feck can a bit of grease interfere with the voltage and current? [/ QUOTE ] Not sure there was a suggestion of this ? You are correct in your statement about the grease acting on the lamp glass when heated [/ QUOTE ] I think you'll find that is what impedance is my good man! Quote Link to comment Share on other sites More sharing options...
S4teve Posted February 21, 2007 Report Share Posted February 21, 2007 Mmmmmmm. When I went to Uni Impedance was a combinion of Resitance of an ac circuit and reactance (of that circuit) - nothing to do with any form of current heating a glass filament lamp (with grease on) Quote Link to comment Share on other sites More sharing options...
P_G Posted February 21, 2007 Report Share Posted February 21, 2007 UBM, I wasn't on about the grease on a bulb from someones finger, one of the original posts was about replacing both bulbs at the same time even if only one had blown and the reason why you would do this rather then replace just the blown one. The grease on bulb bit was potentially another problem / reason why the replaced bulb may blow within the three week timescale originally posted if not fitted with minimal contact from ones sticky mitts. Keep up Quote Link to comment Share on other sites More sharing options...
jackrory Posted February 22, 2007 Author Report Share Posted February 22, 2007 look lads i didn't mean to start a row... Quote Link to comment Share on other sites More sharing options...
P_G Posted February 22, 2007 Report Share Posted February 22, 2007 No row, just a statement of fact. Quote Link to comment Share on other sites More sharing options...
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