The Triumph GT6 front and rear turn signal bulbs both utilize a 1156 size bulb for proper operation. This replacement chart covers vehicle production spanning 1967 to 1973.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 1156 bulb is the sole turn signal bulb type specified for the Triumph GT6 across both front and rear positions for the 1967-1973 model years.
The 1156 is an ANSI-standardized bulb recognized in the United States and Canada, operating at 12 volts with a 21-watt output.
As a single-filament bulb, the 1156 is dedicated to one lighting function per socket, which distinguishes it from dual-filament types that serve multiple functions such as braking and signaling simultaneously.
The 1156 uses a BA15s bayonet base, where "BA15s" denotes a single-contact bayonet fitting with a 15mm base width, a common automotive base type that locks into the socket with a twist.
Because the same 1156 bulb is specified for both the front and rear turn signal positions, the two positions share full interchangeability within the Triumph GT6.