Merkur XR4Ti Map Light Bulb Size

The Merkur XR4Ti map light requires a bulb size of 168 for the interior lighting system. Data for the specified component covers the period from 1985 through 1989.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

Bulb Size by Year Range

Years	Bulb Size
1985-1989	168

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Miniature wedge bulb (T10). 12V, 4.9W.	168

Other Locations

Additional Notes

The Merkur XR4Ti uses the 168 bulb size for the map light across its entire 1985-1989 model year range.
The 168 is an ANSI-standardized bulb, meaning its specifications are governed by a recognized North American standard applicable in both the United States and Canada.
The 168 bulb follows the T10 form factor, which refers to a miniature wedge-base design. The wedge base replaces a traditional metal contact with a pinched glass end that seats directly into a socket.
The bulb operates at 12 volts, consistent with the standard electrical system voltage found in passenger vehicles.
At 4.9 watts, the 168 is a low-wattage bulb, which is typical for interior courtesy and reading light applications where prolonged illumination is expected without significant electrical draw.
Because the 168 is a wedge-base bulb, it is not interchangeable with bayonet-base or screw-base miniature bulbs, even when voltage and wattage ratings are similar.