Rear Lights - Half Illuminated On One Side

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foolhandy
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Rear Lights - Half Illuminated On One Side

Post by foolhandy »

Hello,

I've noticed that with my rear lights the driver's side is a fully illuminated circle, but on the passenger side only a semi-circle is illuminated.

Looking at diagrams, and having taken the unit off to stop a leak (the clip on the unit is broken - thank you gaffer tape!), I think there's only one bulb so...
Is this meant to happen? (unlikely - different shaped lights aren't allowed are they?)
A problem with the bulb? (it can't half illuminate can it?)
A problem with the unit? (my immediate reaction)
Something else?

Before I go off and buy replacement bulbs &/or units any advice as to what might be at fault would be gratefully received. (I am reluctant to take the unit off to investigate as the gaffer tape fix I have has stopped the boot filling with water and so don't want to mess around with that until absolutely necessary!)

Thanks!
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Re: Rear Lights - Half Illuminated On One Side

Post by RUM4MO »

Hi, you might be able to buy a "repair kit" or a new "seal kit" to seal them up again, beware that if you leave these clusters without effective seals, the fixing screws can seize in to retained nut in the cluster - or is t retained studs and a free nut, I've forgotten, but I know this as I've been in that situation and had to force the cluster off with the wing nut and stud seized together, I cleaned it all up separated the wing nut and stud and bonded the stud back into the cluster.

I think that there are two bulbs maybe for the tail light, one half of the brake/tail and another small single filament bulb - check the working side and remember Halford's bulb listing might not be very accurate!
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foolhandy
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Re: Rear Lights - Half Illuminated On One Side

Post by foolhandy »

Thank you. You've confirmed my thoughts that I really need to get a new unit - the boot is wet again and that's where it's coming in. Just have to make sure that the top clip comes with the replacement unit...

As for the bulb, following your message I did some digging online and found this. There are two bulbs, and the one that's gone is [5] on the diagram. Just got to work out which bulb it is now as it's not a stop-tail (the stop light being [3]) and don't know if it's a 380 or 382. Every car I have involves detective work to find out what bulbs are used!

Thanks again for your help. :)

vw polo lights rear.jpg
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tommy.horsman
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Re: Rear Lights - Half Illuminated On One Side

Post by tommy.horsman »

foolhandy wrote: Sun Dec 22, 2019 4:13 pm Thank you. You've confirmed my thoughts that I really need to get a new unit - the boot is wet again and that's where it's coming in. Just have to make sure that the top clip comes with the replacement unit...

As for the bulb, following your message I did some digging online and found this. There are two bulbs, and the one that's gone is [5] on the diagram. Just got to work out which bulb it is now as it's not a stop-tail (the stop light being [3]) and don't know if it's a 380 or 382. Every car I have involves detective work to find out what bulbs are used!

Thanks again for your help. :)


vw polo lights rear.jpg
Yes there is def two bulbs as i replaced mine yesterday with half circle on rear drivers side
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tommy.horsman
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Re: Rear Lights - Half Illuminated On One Side

Post by tommy.horsman »

tommy.horsman wrote: Sun Dec 22, 2019 7:16 pm
foolhandy wrote: Sun Dec 22, 2019 4:13 pm Thank you. You've confirmed my thoughts that I really need to get a new unit - the boot is wet again and that's where it's coming in. Just have to make sure that the top clip comes with the replacement unit...

As for the bulb, following your message I did some digging online and found this. There are two bulbs, and the one that's gone is [5] on the diagram. Just got to work out which bulb it is now as it's not a stop-tail (the stop light being [3]) and don't know if it's a 380 or 382. Every car I have involves detective work to find out what bulbs are used!

Thanks again for your help. :)


vw polo lights rear.jpg
Yes there is def two bulbs as i replaced mine yesterday with half circle on rear drivers side the bulb is a 12v r5w
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Re: Rear Lights - Half Illuminated On One Side

Post by RUM4MO »

Also, while there is a gasket as shown to seal the rear light clusters, there should also be 2 smaller gaskets around the fixing screws - make sure that they are still there, I think that you can buy them or maybe just make some up, as that will be probably where the water is getting in, or one of the places if these small seals are missing or damaged.
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Re: Rear Lights - Half Illuminated On One Side

Post by foolhandy »

Thanks for all you replies. :)

I've ordered a new unit, £20 from eBay with bulbs! That small gasket you talk of is there, but one of the fixing screws/clips is broken. That's where the water was getting in really badly, so I've had to create a gaffer tape channel to try and redirect the water! It's been reassuring to read your confirmation of what I need to do. It's only £20 but I've got enough not-needed car bits that I bought on a hunch around here as it is...
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Re: Rear Lights - Half Illuminated On One Side

Post by RUM4MO »

foolhandy wrote: Mon Dec 23, 2019 3:01 pm Snip -- Snip
I've got enough not-needed car bits that I bought on a hunch around here as it is...
Well that is a "disease" that does not necessarily go away when you get older - this I know have some 2000 VW Passat 4Motion new upgrade parts, the initial cost of which would make your toes curl, gulp.

I had forgotten about the other spring clip locaters which also have small seals round them, first time that I needed to take these clusters out to replace a tail/brake bulb, it was quite a challenge, I've even now bought a "lights puller" from Laser Tools for my wife's 2015 Polo and some other cars, but then I kind of like to buy tools!
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foolhandy
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Re: Rear Lights - Half Illuminated On One Side

Post by foolhandy »

Apologies if this seems like resurrecting an old thread, but it was Christmas and then I broke my elbow and typing wasn't really an easy thing for a couple of weeks so...

An update. The new light unit arrived (with clips!) and, pre-elbow injury, I fitted it, drained the spare wheel well of several gallons of water, and changed the bulb that wasn't working with the one that came with the new light unit. I didn't check the 'new' bulb before I fitted it, which I should have, because when I tested it I found it was blown too. So either the 'new' bulb was blown when I fitted it or there's something in the wiring that's causing that bulb to blow. Unable to test it properly at the time because I don't really know how to, I dug out some LED stop/tail bulbs I have in my car parts mountain and after filing off one of the offset pins so they would fit stuck them in and they work a treat. Presumably, as I guessed, they can handle the extra current if it exists and so won't blow. There is still, obviously, a potential underlying issue here if the 'new' bulb was OK when I put it in, but everything is working OK for now and my elbow isn't really in any state at the moment for any vehicle maintenance.

And the water leak - despite the recent deluges the spare wheel well is dry as a bone so as expected the new light unit with its proper clips and gaskets is working as VW intended. I've added the old unit to car parts mountain.

A belated Happy New Year and thanks again for your helpful replies with this. :)
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Re: Rear Lights - Half Illuminated On One Side

Post by RUM4MO »

As far as I can think, there is no wiring issues that can cause a working bulb to fail early in life, the only thing that could cause that is the alternator overcharging and allowing the voltage to be too high when the engine is running, so that would be easy to check with a cheap digital voltmeter, ie DVM or DMM - same thing.

Why not buy a couple of new bulbs from a good source - whatever that means! So that you are starting from a known standpoint, this ebay sourced light assembly might just have been fitted with cheap bulbs and this one was the most fragile. Halfords tend to sell Bosch branded bulbs, but I've almost convinced myself that their Halfords own brand bulbs have the same production markings on them, like maybe both from the same factory.
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