I have a few bulbs out on my 2000 ML430 and am going to swap them for white LED. Need to know the size so I can swap them out. I'll add a "How to" and before and after pictures if anyone else plans to do it also.

I'm going to pull the cluster myself this weekend and see if I can answer my own question.

Considering that these cars are 9-16 years old, it may come as no surprise that bulb replacement has been done before and information recorded, for you to find if you had looked. Search the forum.

The Illumination Bulbs are "194 bulbs".

Thanks for not helping or reading at all. I already know how to pull the cluster and how to swap a bulb. But they appear to be in a unique socket and I'm not seeing any bulb size written on them. I was looking for the bulb size and nothing else. Thanks.

Well since you already know how to do everything except change a light bulb, the answer you wanted is W2.1x9.5d for the larger cluster illumination bulb 12 V 2 W.

The best replacement off-the-self bulb is the OSRAM/Sylvania 161 2.7W at 14V (not the 164 at 3.8W). The physical size is the same, however.