A light guide and module for motor vehicles that directs light generally along a horizontal axis. The module includes an array of light sources, an array of reflectors and a light guide. The light guide defines a body having opposed upper and lower walls. Formed in the lower wall is at least one prismatic structure having a reflecting surface oriented to reflect light based the principle of total internal reflection and to redirect light toward the upper wall. Formed in the upper wall is at least one decoupling prism element. The decoupling prism elements corresponding in number to the prismatic structures and are located in the upper wall so as to receive redirected light from its corresponding prismatic structures. The decoupling prism element includes a second reflecting surface that reflects light redirected from the first reflecting surface. This second reflecting surface reflects light toward an output surface of the decoupling prism element based on the principle of total internal reflection and defines a vertical spread of light. With the present invention, light emitted from the output surface of the decoupling prism element can be directed generally along the horizontal axis when the upper surface is oriented significantly less than 90° relative to the horizontal axis.