The following Mercedes part numbers apply to bulbs utilized in the instrument cluster, clock and heater controls:
1) 2W bulb used on everything except the heater controls: N072601 012800
2) 2W bulb used on heater controls (2 each): N072601 012110
3) 4W bulb used as an option for illuminating the instruments and clock: N072601 012900
Please note that the Mercedes Electronic Parts Catalog (EPC) shows the SAME part number for heater controls and instruments/clock. This is incorrect, as the heater bulbs have a different bayonet fitting.
The 4W bulb has been referenced throughout this site to better illuminate the instruments and clock. This would require 7 bulbs total: 2 each for the Tachometer; 1 each for the Center Instrument Cluster; 2 each for the Speedometer and 1 each for the clock. It should be noted that there are six (6) additional bulbs in the Center Instrument Cluster for turn signals, low fuel light and 3 idiot lights...these should remain as 2W bulbs