Fuse blows for interior lights

Could be the LCM, but I doubt it. Solder a 12v bulb to an extra fuse (not easy) plug it in, it will light up because of the short. If it only lights up when a door is opened, check each light socket and bulb. If your jury rig bulb goes out, you've found the short. If the test bulb lights with the doors closed, it's a wiring problem somewhere, or possibly the LCM. A big question is does the fuse blow immediately, or after a door is opened? This is a tough one. Someone else may know if the lcm can do this.

I have 2007 Grand Marq with same problem - no interior light and keeps blowing fuse (#18 ). I dropped driver side visor and discovered bare wire shorting out against one of the visor mounting screws. Wrapped bare wire with electrical tape, remounted visor and problem solved. Several years ago we had a Nissan Quest with same problem and paid dealer $500 to find the bare visor wire, so that's the first place I looked on my Merc.

Blowing the # 18 fuse (interior lights). Removed the sun visors and found melted wires for the right hand side shorted together. Dropped the headliner down for access and cut back the damaged wiring (both sides) and insulated. No real need for a lighted visor mirror anyway; I've had them in my last 5 vehicles and never used them.

Fuse for headlights blows after using turn signals or flash to pass. Can anyone help?

Fuse blow immediately