i agree with All of the above and as a Richard said if you are lucky it may only be the connector plug under front of tank, pull the plug and check there is no burnt or discoloured connector pins and while you are at put a good dose of Dielectric Grease in the plugs as this helps continuity, if the wire is burnt or discoloured at either side of the plug make a bridging connector as Richard (canberraR3) had to do and either buy (EasternBeaver) or make up a ign bypass lighting relay harness. I haven't had a chance yet but promised someone else I would make a drawing and list plus instruction to make your own, I will endeavor to get it done later after I Finnish work in morning