Ballast Units-How do they fail?

[emailthebrowns@]

My error message "dipped beam right" went away 2 days ago was replaced with "no malfunctions" and light started working again.
However got myself a small tool kit together and removed bottom plastic engine cover as suggested by Kuazizul. access no problem this way. Removed ballast unit cleaned terminal connections and reassembled.
Every thing still OK.

The light has now gone out again!

My question is if the ballast unit was on its way out would it be a bit hit and miss for a while before giving up all together or would it just fail, should i be looking for another fault?

 

[stwat]

Dry solder joints and/or blown capacitors. Both heat related and in most cases easily fixed.

 

[emailthebrowns@]

Thanks for the reply. Would these issues cause them to fail gradually i.e work one day and not the next or would they just fail in one go and never work again?
Trying to narrow down my problem.

 

[andy27168]

Hi,
I wouldn't just assume its the ballast, swap the lamps (bulbs) from one headlight to the other, the lamps are more likely to fail than the ballast.

 

[emailthebrowns@]

Already done that, and also swapped over the black square box's with green wires attached. (ignite units?)
Will swap the ballast units at the weekend to check them out.

 

[MancMike]

Would these issues cause them to fail gradually

Dry solder joints can. As they'll make and break, so will be intermittent in their function, but this causes arcing and corrosion so the joint degrades over time to the point of total failure.

If you can locate a dry solder joint, though, it's an easy fix!

 

[emailthebrowns@]

Problem solved. Ordered a replacement ballast unit of ebay £25 (from a Renault breaker, these same ballast units used on Mercedes W211 are used on Jags / Lexus / Renault so worth checking around if looking for used replacement.)
For information both left and right are identical and both can easily be accessed from below with the bottom splash plate removed.
Bottom splash plate removal 8mm socket required (8 hex head screws to remove)
Ballast unit removal torx 20 driver required (3 screws per ballast unit)

Thank to every body for help and information.