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C4 - DS4 Owners :: Forums :: Styling Performance and Upgrading :: Interior and lights

Constantly on LED stop lights

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mduque   
Wed Aug 19 2015, 03:41pm
Member No: #41758
Joined: Aug 19 2015
Location: London
Hello. I have just recently changed the P21W stop light rear bulbs with P21W 19-LED Brake/Stop Bulbs Upgrade Lights. However, when the park lights are turned on, the new LED brake lights and the high mount third stop lights is constantly turned on to bright. Even if the brake pedal was pushed, nothing happens to indicate a stop. When the park light switch is turned off (during daytime) and the brake pedal is pushed, the brake lights come on fine. Can anybody help please.

I have a 09-reg SX HDI 1560cc DIESEL, 5 Door MPV.


routemaster1   
Wed Aug 19 2015, 04:17pm
Member No: #574
Joined: Jul 08 2007
Location: Dorset
What happens if you put the original bulbs back? The CANBUS system does not like changes to the system, so the LEDs may not be compatible.
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 mduque (21 Aug 2015 : 02:53)
Dave_Retired.   
Thu Aug 20 2015, 03:08am

Member No: #1
Joined: Aug 07 2006
Location: Northumberland
Try rotating the bulbs 180 degrees
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 mduque (21 Aug 2015 : 02:53)
mduque   
Thu Aug 20 2015, 03:46am
Member No: #41758
Joined: Aug 19 2015
Location: London
One of the original stop light bulb is not working hence I had to change the bulbs. When one side is using the LED bulb and the other side if using the original working bulb, the whole brake light system (including the high mount third light) is still lighting brightly when switched to park lights. No difference when brake pedal is applied.

Cant rotate the bulbs as the base is bayonet type (as above in picture). Either way it is the same.
mduque   
Thu Aug 20 2015, 03:50am
Member No: #41758
Joined: Aug 19 2015
Location: London
I have asked the retailer about using a CAN bus LED and they said I might need resistors to add to the LED bulbs I just bought from them.
Biohead   
Thu Aug 20 2015, 11:31am

Member No: #6049
Joined: Nov 05 2008
Location: Bracknell
In general, the canbus system does not like LEDs - but you may be able to get LEDs which incorporate some resistors too to trick the bus into thinking there is a load there.
It's not guaranteed to work, but you stand a better chance with these type of " canbus aware LEDs".
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 mduque (21 Aug 2015 : 02:53)
mduque   
Fri Aug 21 2015, 02:52am
Member No: #41758
Joined: Aug 19 2015
Location: London
Update fellas. After moving and twist the LED bulbs, I still have not managed to make it work as it should. At daytime when park-lights switched-off, thing work properly. When park-lights switched on at night, the brake-lights glow bright (including the high mount third stop-light). No difference still when brake pedal applied. As it continues to glow bright and a danger to drive at night (as driver behind wont know if I am stopping), I had to go to halfords and buy the P21W bulb replacement. On putting it on, everything works fine EXCEPT that the nearside brake lights glow bright on the large filament and when brake pedal applied, the small filament lights adding off a small brake-glow unlike the offside brake light which glows on the smaller filament and when brake pedals applied, the bigger filament glows giving off a strong brake-light glow. Sigh!!!
routemaster1   
Fri Aug 21 2015, 03:28am
Member No: #574
Joined: Jul 08 2007
Location: Dorset
You haven't indicated what car it is. If a C4, I would check 2 things. First, check the wiring loom between the car roof and the tailgate. It is a known issue for these to chafe and give all sorts of problems. Also ensure that the light units are properly earthed. I'm sure you have seen cars where the rear lights are OK, and on brake application one stop light works and the rear light on the other side goes out. A poor earth is the cause of this.
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 mduque (21 Aug 2015 : 15:09)
mduque   
Fri Aug 21 2015, 05:04am
Member No: #41758
Joined: Aug 19 2015
Location: London
Thanks for the tip routemaster...I have a C4 Picasso 09-reg 1.5 vtr. I will check and look at your suggestions.
Dave_Retired.   
Fri Aug 21 2015, 06:35am

Member No: #1
Joined: Aug 07 2006
Location: Northumberland
It could also be a damaged light unit due to corrosion of the contacts etc.
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 mduque (21 Aug 2015 : 15:02)
Honest   
Fri Aug 21 2015, 01:36pm
Member No: #35215
Joined: Apr 20 2014
Location: Russia
Hi, mduque! "Cant rotate the bulbs as the base is bayonet type (as above in picture). Either way it is the same. " It is not the same. The LED works only from a direct current but the bulb works as from the direct current so from alternating current. It works when a polarity is truth. You are trying to change the polarity on wires in a terminal block. When it will not help than take into consideration that the canbus system doesn't understand that there are lights. Biohead is truth. The LEDs have a high resistance. You have to unpack the LEDs (there is a sealant)and to solder resistors on free contacts. It will be done by any electrician.
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 mduque (21 Aug 2015 : 15:02)
routemaster1   
Fri Aug 21 2015, 02:29pm
Member No: #574
Joined: Jul 08 2007
Location: Dorset
As the car is a Picasso and not a Grand, I'm assuming that the rear lights are twin filament, and that the LEDs are also capable of providing both low output rear lighting and higher output brake lighting. Of so the bulbs are likely to only fit one way as the pin depths should be asymmetric. Also, if with 2 ordinary bulbs the system does not work properly it seems to point to a wiring fault.
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 mduque (21 Aug 2015 : 15:09)
mduque   
Fri Aug 21 2015, 03:08pm
Member No: #41758
Joined: Aug 19 2015
Location: London
Update Fellas. The wiring as all intact and not chaffed or corroded. Contact as all snug and fit. Honest- thanks for the clarification. Too complicated for me to unpack and solder. I am scared to do it. Yes routemaster - it is a picasso with twin filament on the brake bulbs. Yes, the LEDs I bought have high and low output. Indeed the pin depths on the LED bulbs are symmetric not like the original bulbs which are asymmetric in placement. Two ordinary bulbs (which I just bought from halfords)works ok except that the nearside lights on the low output filament on braking and lights on the high-output filament when rear-lighting. I cant find any wiring fault as all wires are intact and not been repaired or touched at all.
ksibbons   
Sat Aug 22 2015, 05:40am
Member No: #14033
Joined: Jun 05 2010
Location: Bristol
If the nearside bulb is on low power when the brake lights are on and high power when side lights are on, this indicates the bulb is in the wrong way. As the holders are plastic (at least on the C4) it is easy to force the asymmetric pins to go in the wrong way round and give the effect you describe.

For the LED bulb if they have symmetric pins they can not be high/low output. The P21/5W bulb has to go in a specific way for it to work properly- hence the asymmetric pins. I also think the correct code for these are 1157, the bulbs you show in the picture are 1156?
 

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