The Triumph TR6 front and rear turn signal bulbs both utilize a 1156 size bulb for proper operation. The replacement chart covers 1969 to 1976 model years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 1156 is the sole bulb type specified for the Triumph TR6 across all listed turn signal positions and model years.
The 1156 is an ANSI-standard single-filament bulb rated at 12 volts and 21 watts, fitted with a BA15s bayonet base.
The BA15s bayonet base features a single contact pin, which distinguishes it from the dual-pin BA15d base used on double-contact bulbs; the two are not interchangeable.
Being a single-filament bulb, the 1156 serves one function per socket, which is consistent with its use in dedicated turn signal housings rather than combined stop/turn applications.
The Triumph TR6 (1969-1976) uses the 1156 for both front and rear turn signals, meaning the same bulb type is shared across all four turn signal positions throughout the entire production run covered by these specifications.
The ANSI designation of the 1156 indicates conformance to a standardized specification recognized in the United States and Canada, covering electrical and physical parameters.
At 21 watts on a 12-volt system, the 1156 draws approximately 1.75 amperes per bulb, a figure relevant to assessing load on the turn signal flasher relay.
Substituting a dual-filament bulb such as the 1157, which shares a similar but offset dual-pin bayonet base, into a BA15s socket is not mechanically compatible and would require socket modification.