Lim,

The older the car gets, the duller the instrument lights will become. The-dash-cluster-bulb-light is re-/deflected by a diffuser like plastic part inside the dash cluster. If you insert a bulb with a higher wattage, this plastic diffuser will melt and get a brown tint (=dull light).

If you take out the dash cluster, you can read at the back of the cluster what bulbs should be used (I thought the bulbs are 2 Watt??) and if you peak in the cluster bulb holes, you can see whether the plastic diffuser already turned brown or not...

greetingz,

__________________
1990 300SL-24
1993 C250D with a minor 600+k kilometer
www.MBenzNL.com(the Netherlands)