On my 2001 SLK 320 that I purchased back in January, I decided to update my side markers with canbus yellow LED's with a smoked lens. This threw the bulb out warning. I figured out that the sidemarkers are connected to the parking lights in my spyder headlights. Instead of attaching resistors in the side markers, I decided to attach a 50watt 8 Ohm resistor using 18 gauge braided wire (smaller the gauge = more resistance, which could burn out the wires but 18 gauge is good. I needed more resistance so I hooked in my halos to the LED parking lights wires (not signal lights). On the spyder headlights, I replaced my signal lights with LED's dual intensity (1157 canbus from brightlightleds.com). This fixed the bulb out warning as there is enough resistance in the circuit to fool the computer.