With the Direct (or Group) Selection Tool select the car outline, now a clipping path, and apply a color to the stroke and/or fill. The "Clipping Mask>Make" command removes such attributes, and they must be reapplied if you want them.
@Monika - hey, your answer reminded me of the Photoshoptroll.com site... LOL!
Actually, this has been a request for years: that clipping paths RETAIN their attributes... at least Fill and Stroke... after choosing make Clipping Mask. Also that a clipping mask that has a fill, is actually able to be selected by clicking on the fill "visually" without resorting to only being able to click on it's path (or the layer panel selector).
As evidenced, the current behavior totally screws up new users to Illustrator.
Actually, this has been a request for years: that clipping paths RETAIN their attributes...
well. Yes, it has. And actually you can do that since version CS5 by working in Draw-inside-mode.
But I'm not good at reading thoughts. And my crystal ball has fallen to the floor long ago. So I wasn't joking around, I wanted to know what was the problem.