So, As title says , my right bixenon has right color (white/blue) , but left is yellow, I tried changing that left bulb and bought OSRAM XENARC exact as right one , but it is still yellow , so what is the problem ?

Ballast may need replacing, but usually a ballast problem is noted by flickering or the bulb not igniting at all.

 

Are the bulbs rated at the same temperature (I.e. the same "K" rating)?

I thought that Ballast are already fitted on bulb, it's D1S

Edit just seen you said you've changed the bulb

Edited 27 August, 20187 yr by a666andy

Try swapping the bulbs over, you can at least then rule out the bulb.

1 hour ago, adoni546 said:

I thought that Ballast are already fitted on bulb

 

The ballast is a separate module, that is mounted under the headlamp, and they usually outlive the xenon bulb

I swaped bulbs but problem is still same, left headlight is more yellow then the right  @silver1011

You could swap ballasts then (very tricky unless you remove the wheels, wheel arch covers and maybe even the front bumper (depending on the tools and type of hands that you have) ... or, maybe something happened to the left lens within the headlamp (discoloration, water ingress, ...)

I feel sure the yellow bulb is not receiving the correct voltage.

Please don't try testing that with a multimeter though.

4 minutes ago, superbdreams said:

Please don't try testing that with a multimeter though.

 

Why? It's only 12 V ... ... if you don't count the ignite 20,000 V and the running 85 V ...  

I was referring to the higher voltage, how would you disconnect before it dropped?

1 hour ago, superbdreams said:

how would you disconnect before it dropped?

 

I think it would auto-disconnect you ...

 

You could make a break out point on the cables and measure the voltage after the initial strike and compare left and right?

Perhaps buy a "happy shopper" or "superluckygood tm" cheap make of meter just incase.