strange LED Sidelight problem

[kinkuu]

Hi. Recently I decided to put in LED bulbs in place of the normal bulbs in the two front sidelights. They worked fine but I got an orange warning light come up on the dashboard indicating a bulb was not working somewhere, but all lights were in fact working. I think the car didn,t like the LED bulbs so I put the old normal bulbs back, but neither left or right bulb would light up. The fuse is fine and when I put one of the LED bulbs back in it lights up fine, so there is power going to the light, but when I replace it again with the original bulb, again it does not lightup. I have read that the LED bulb might not be CANBUS. I don,t know what that means, but it seems the LED bulbs have upset the electrics somehow. Does anyone have any experience on this as I would like to get the original bulbs working and not use LED bulbs. Any advice gratefully received as I really can,t figure this out

 

[Trickythemerc]

Have you tested the original 501 bulbs on a remote power supply. If you have power at the bulb holder the 501s should work fine.

 

[Chrishazle]

Sounds like the original bulb is blown, and the LED you installed is not canbus error free. However, be aware that LED's generate heat, I've tried quite a few in my S203 and S204, they don't last long, and one type I tried has a plastic lens on the front which had melted/deformed hence my comment about heat and ventilation. Another had sharp edges that caught on the back of the light when pulling the bulb holder, dropping the LED bulb into the headlight assembly irretrievably.

On my S204 the side and position lights are a pig to change, in the end I gave up (after trying about 5 different types of LED) and went back to standard bulbs.

 

[stephenmercedes]

Simple solution - go online and buy the size of bulb and make sure it is listed, 'CanBus error free'. Fundamentally, LEDs draw a very small current, fooling your Merc into thinking the bulb is blown, hence the 'fault'. (the error free have a built in resistor to fool the car's CanBus system & emulates the original resistance of a standard bulb making the car think all is OK, so no error). If you don't trust 'online', pop down to your local Halfords, they do a great range of 'error free' LED sidelight bulbs that'll sort you out. I've been using LED bulbs for years now, no issues at all

LED side bulbs

 

[kinkuu]

Simple solution - go online and buy the size of bulb and make sure it is listed, 'CanBus error free'. Fundamentally, LEDs draw a very small current, fooling your Merc into thinking the bulb is blown, hence the 'fault'. (the error free have a built in resistor to fool the car's CanBus system & emulates the original resistance of a standard bulb making the car think all is OK, so no error). If you don't trust 'online', pop down to your local Halfords, they do a great range of 'error free' LED sidelight bulbs that'll sort you out. I've been using LED bulbs for years now, no issues at all

LED side bulbs

 

[kinkuu]

Hi, thanks all for your help. To stevemercedes, I understand why the error light appears with the LEDs but I don,t understand why the original bulbs ( type435 H6W) don,t work when I re install them, although the error light goes off.. It,s like the car doesn,t see or recognise them. The bulbs are fine, I even bought new ones but they still don,t work. Is there any type of reset you can suggest?
Unfortunately Halfords only do a standard version of this bulb type, no error free LED available.

 

[stephenmercedes]

The first step I would do, and I know it's a pain, is connect a multimeter to the sidelight connection to see if it's getting 12v...

 

[PGW124]

The canbus can get upset and stops sending the 12v. Next time you have a known working old style bulb installed, turn off the ignition and lock the doors with the fob. Then try again.