Boot lid brake light

[GurjM]

Hi,

Have a E270 cdi 2003 and the brake light in the boot lid has half stopped working, does the whole unit need replacing or can the individual LED be changed.

Is it an easy job to replace the whole unit?

Thanks.

 

[television]

I would take it out, and see if it can be opened up, if it can, then yes any LED's can be replaced or the break in the PCB fixed. You are in north Herts, replacements LED's can be bought from Farnell in North hants or CPC in Watford. If half not working it sounds more like a break in the PCB.

Malcolm

 

[merc c200k]

Hi

I did this one a couple of weeks ago on my 2002 C200, so I doubt yours will be much different. Simply remove the lining from the boot lid you should be able to see the back of the brake light, remove the torx screws that are in the back of it and flick the metal clips off that the torx screws held in place. It should now be possible to remove the lamp cluster from the boot by pushing it out, now disconnect the power connector.

With some fiddling it is possible to remove the PCB from the housing I found using a screwdriver to prise the clips that hold the PCB down when the PCB is above the clips turn it to about 45 degrees and it should wiggle out!

The LEDs are surface mount and each one is connected to the 12v feed (when the brake is pressed) via a resistor, my guess is if half are out you defiantly have a brake in the tracks on the PCB and it will most likely be on one or both of the tracks that run from the power connector at one end, once the fault is located you can scratch off the paint that covers the track until you see the copper then simply run some solder over the brake.

To help find the fault it could be possible to re connect the PCB to the car, get someone to press the brake pedal and flex the PCB to see if the other LEDs come on again by flexing the PCB. Whilst the board is out you may as well re solder each component and then test the PCB as above before re fitting, flex the PCB if the LEDs stay on the jobs good. Refitting is a reverse of above.


Hope this helps

Mark

 

[television]

Hi

I did this one a couple of weeks ago on my 2002 C200, so I doubt yours will be much different. Simply remove the lining from the boot lid you should be able to see the back of the brake light, remove the torx screws that are in the back of it and flick the metal clips off that the torx screws held in place. It should now be possible to remove the lamp cluster from the boot by pushing it out, now disconnect the power connector.

With some fiddling it is possible to remove the PCB from the housing I found using a screwdriver to prise the clips that hold the PCB down when the PCB is above the clips turn it to about 45 degrees and it should wiggle out!

The LEDs are surface mount and each one is connected to the 12v feed (when the brake is pressed) via a resistor, my guess is if half are out you defiantly have a brake in the tracks on the PCB and it will most likely be on one or both of the tracks that run from the power connector at one end, once the fault is located you can scratch off the paint that covers the track until you see the copper then simply run some solder over the brake.

To help find the fault it could be possible to re connect the PCB to the car, get someone to press the brake pedal and flex the PCB to see if the other LEDs come on again by flexing the PCB. Whilst the board is out you may as well re solder each component and then test the PCB as above before re fitting, flex the PCB if the LEDs stay on the jobs good. Refitting is a reverse of above.


Hope this helps

Mark

Mind if I just add something to your good answer, if the PCB is cracked it is always better to bridge it with a short wire,soldered over the crack.


Malcolm

 

[GurjM]

Thanks guys, have located the problem to 7 LED's which are not working.

Malcolm - any Idea which LEDs these are, I have looked on the cpc website but can see the correct ones, do they need to be 12volt?

Thanks.

 

[television]

No Sir, No such thing as a 12 volt LED, also you would never get 7 LED's all going at the same time,!!!!! they are wired in serries and 1 has gone, they are all around 1.8-2volt, I think you need the brightest ones, never done it myself.
!2 volt divide by 7= 1.7

Best regards malcolm