Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie
Please note that it is not permitted to have referral links posted in your signature. Keep these links contained in the appropriate forum. Thank you.

https://www.boards.ie/discussion/2055940817/signature-rules
Hi there,
There is an issue with role permissions that is being worked on at the moment.
If you are having trouble with access or permissions on regional forums please post here to get access: https://www.boards.ie/discussion/2058365403/you-do-not-have-permission-for-that#latest

2004 Merc W211 1 x main beam stuck on.

  • 18-01-2019 7:04pm
    #1
    Dermo123
    Registered Users, Registered Users 2 Posts: 384 ✭✭


    A few weeks ago I noticed that the nearside mainbeam light was turned on. The car was parked up for a week and nobody went near it. It just for no reason turned itself on while sitting there.:confused:
    The lightswitch is in the off position and the indicator is off.

    So I tried the following.
    Disconnecting battery for a few days.
    Removing all relays I could find in engine bay and in boot.
    Drive it around to see if an error message appears in dash.
    No malfunction is displayed on dash.

    The only thing I can do is pull the cable from the bulb for now.
    However it failed the NCT for nearside main beam as well as a ball joint.

    Does anyone have any ideas what this might be other than what I have mentioned above.:confused:


Comments

  • #2
    scannerd
    Registered Users, Registered Users 2 Posts: 236 ✭✭scannerd


    With relay removed the light stays on?


  • #3
    Dermo123
    Registered Users, Registered Users 2 Posts: 384 ✭✭Dermo123


    scannerd wrote: »
    With relay removed the light stays on?

    Yes. I had all relays out and thought light would go out that I could find. Confused.


  • #4
    joujoujou
    Registered Users, Registered Users 2 Posts: 13,978 ✭✭✭✭joujoujou
    Unregistered Users


    Unplug light switch for a while.


  • #5
    scannerd
    Registered Users, Registered Users 2 Posts: 236 ✭✭scannerd


    agreed with above, try all possible simple fixes first but sounds like you have a short to positive somewhere between the relay and the the lamp, start with testing the supply pin to the headlight, at the relay ie with the relay pulled it should not have + power. this most often happens at connectors via water egress


  • #6
    paultronix
    Registered Users, Registered Users 2 Posts: 150 ✭✭paultronix


    Replace your passenger side Sam unit it's located under the carpet at passenger feet, a 2nd hand one will be fine,no coding required.At a guess I'd say you possibly have a battery drain problem too.


  • Advertisement
  • #7
    Dermo123
    Registered Users, Registered Users 2 Posts: 384 ✭✭Dermo123


    paultronix wrote: »
    Replace your passenger side Sam unit it's located under the carpet at passenger feet, a 2nd hand one will be fine,no coding required.At a guess I'd say you possibly have a battery drain problem too.

    Thanks for replies. Never heard of the SAM unit before but googled it there and it does seem like a possibility. I do not have other malfunction that i know of. Battery drain problem maybe but car will start Ok evening if left idle for a week or more.

    Ill see how the SAM Replace enjoyed goes.


  • #8
    Dermo123
    Registered Users, Registered Users 2 Posts: 384 ✭✭Dermo123


    Well eventually I got the SAM module on ebay second hand. £8.99 plus €3.75 to get vis Addresspal. Plug and play and all good now.
    Thanks to all above for very helpful suggestions.


Advertisement