The Ford Flex uses two distinct bulb sizes across its side marker positions: the 168 for the front and the 194 for the rear, both of which are ANSI-standardized miniature wedge bulbs of the T10 type rated at 12 volts.
Both the 168 and 194 bulbs share the same T10 wedge base form factor, which means they are physically interchangeable in terms of socket fit. However, their wattage ratings differ, with the 168 drawing 4.9W and the 194 drawing 3.78W, making them electrically distinct components.
The front side marker on the Ford Flex uses the 168 bulb across the 2009-2018 model years, with all entries carrying the condition "With Halogen Capsule Headlamps."
The rear side marker uses the 194 bulb across the 2009-2019 model years, also exclusively under the "With Halogen Capsule Headlamps" condition.
The halogen capsule headlamp condition noted in every specification entry indicates that these bulb sizes apply specifically to Ford Flex vehicles equipped with that headlamp configuration.
The 168 and 194 designations are ANSI standards recognized in both the United States and Canada, meaning the bulb specifications conform to a defined set of electrical and physical parameters established by that standardization body.
The T10 wedge base, shared by both bulb types, is a common miniature automotive format in which the glass envelope itself acts as the retention mechanism within the socket, with no separate metal base pins.