Tractor pre start glow coil failed to glow. Serviceman installed auxiliary push button starter which worked for couple of weeks. Decided to remove this and go back to glow coil. While installing it glow coil lit up very bright red hot and blew element. Managed to pull the fused ends and twist together. Positive glow coil wire stayed connected to starter switch and negative ( black wire with white stripe) was loose. not sure which starter switch terminal to connect it to. I tried connecting it to same colored( black with white stripe) wire on starter switch. Started tractor but when I switched ignition off coil was still smoking so I disconnected wire to prevent possible damage. The terminals at rear of starter switch marked as 17, 30,ac, 50 & 19. Like to know which one to connect glow coil to