How I solve it was to take rides to do fun things. We would go to visit people and he loves visiting people. We would also get into the car to go to the park, even though it was only 3 blocks away. We would also always go to places like Wendies or KFC, some place that he would get a treat. I know I shouldn't be feeding them people food, but occasionally, is okay as far as I am concerned.
In other words try to do things that your dog will associate good things
with the car -- that something good or fun is going to happen at the end of
the trip. Be patient. She will get used to it as soon as she sees there is
nothing bad associated with the car. It took a very long time for my yorkie
to relax. Even after about two years, you could tell my yorkie was still
apprehensive about it by the way he totally was glued to one of the other
dogs. But now after 4 years, you can tell he is just as comfortable as the