Hello, the front turn signals on a 98 c230 should be seperate from the headlamps.
1. open the hood and look behind the left side headlamp assembly towards the turn signal lamp.
2. locate a tab which is part of the turn lamp assembly. it should be towards the fender side of the lamp.
3. push it inwards while pushing out with lamp.
4. unplug the connector which just pulls off. may require some force.
5. turn the socket counter-clockwise about a 1/4 turn and pull out.
6. push in on the bulb slightly while again turning counter about 1/4 turn and pull out.
7. be sure to replace with the same type of bulb. match up the contacts and side pins.
8. install in reverse order.

