Break light out, tail is ok. New bulb put in.
Hi, as the tail light gets its supply from the ignition switch, it sounds like you have an issue with either a bad earth on the rear light or a break in the wireing from under the seat to the light, lift the seat, pull apart the loom that feeds the rear light, you will have a green, (earth) and a brown = rear tail light, and green/ red brake light, as the tail light is working you can use the rear lite supply to check the circuit from the connection to the light. ,under the seat disconnect the brown, and the green/red and plug them together in reverse, now if the system is ok the rear light opperation, will light up the brighter fillement of the bulb and the rear light will look brighter than previouse, if it does noy light, then the problem lies in the wire from that point to the light, if it does light return the wireing back to normal, find the rear brake switch, separate the two wires on the loom end plug both of the wires togeter without the switch, if the light works then the switch must be replaced, good luck, paul