The Merkur Scorpio front turn signal bulb uses a 1157 size, while the rear turn signal bulb requires a P21W size. Replacement bulb specifications for the Merkur Scorpio span a 1988 to 1989 production chart detailing the required sizes.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Merkur Scorpio uses two distinct bulb standards across its front and rear turn signal positions for the 1988-1989 model years, reflecting a mixed-standard electrical design.
The 1157 bulb, specified for the front turn signal, is an ANSI-standard type common to the United States and Canada markets. It operates at 12V and carries a dual-filament configuration rated at 21W and 5W, housed in a BAY15d bayonet base.
The dual-filament design of the 1157 allows a single bulb to serve two lighting functions simultaneously, typically combining a brighter signalling output with a lower-intensity running or parking light function.
The rear turn signal on the Merkur Scorpio uses the P21W bulb, an ECE-standard type associated with European and international vehicle markets. It operates at 12V with a single filament rated at 21W.
The P21W uses a BA15s bayonet base, which is a single-contact fitting. This base is not interchangeable with the BAY15d base of the 1157, as the two bases differ in their contact and pin offset configurations.
Because the front and rear turn signals use bulbs from different international standards, substituting one for the other is not possible without a base adapter or socket modification.
The presence of a European ECE-standard bulb at the rear reflects the Scorpio's origins as a Ford of Europe platform, while the ANSI-standard 1157 at the front indicates market-specific adaptation for North American fitment.