Just finished replacing the front amber and aft red marker lights on my 2003 Marquis. The exact replacements on my rig are made by Truck-Lite and are 18300Y and 18300R, yellow and red respectively. My lights, old and new, have TL-18 embossed at the bottom of the lens. Existing attachment holes (4" CtoC) matched perfectly. In my research through the BAC I found many "this might work" references but no exact match. Now you have one.
I found the wiring a bit weird, there are two leads on the lights but the existing wiring had BOTH power and ground, clearly marked, going to each lead. Two wires to a butt connector in and one wire to the light for each lead coming out. No matter how you hooked them up, they worked! I just connected the old leads to the new ones rather than mess with trying to find and shove two 10 gauge wires into one end of a 10 gauge butt connector if I were to do it "right". In my book "right" means it works and is unlikely to cause problems in the future. Took about 5 hours to do front and back, between water breaks and giving my little pink body time to keep from cramping up on top of the ladder. The PO was generous with silicone seal but it came off fairly clean. I used Lexel to waterproof the new ones. Everything lights up so I'm calling it good.
