Upright, the Chariot is all about moving forward. Not just about charging ahead, but rather seeing where you want to go, picking up the reins, taking control of inner and outer forces, and directing everything forward. Hence, it is a card of great determination and confidence, motivation and leadership. Without these, there's no making the chariot go where you want it to go. So what about reversed?
1) Opposite: image-wise, there is some confusion with the chariot. It's about movement, victory and going forward; but the image in Rider-Waite at least, is of the chariot at rest. Either after it's victory or before. This makes the opposite or inverse interpetation a bit difficult, as the most obvious one would be a chariot at rest. NOT moving as compared to moving.
So let's simplify this opposite; we'll leave the movement interpeations for the other two and go for the "victory" interpetation on this one. Obviously, the opposite would be defeat. The chariot did not conquer either the inner or outer forces; it lost the battle to control the horses, lost the battle against whatever it was fighting. It might even suggest that the querent gave into cowardice. He didn't try to show the horses who was boss, didn't try to barrel though his enemies--he just hid in his chariot hoping not to get hurt, taking no chances.
2) Blocked: as the upright card often focuses on controling the horses, on determination and direction, we can see that a blocking of these energies leaves the querent at loose ends. Ever driven with someone who has absolutely NO sense of direction? That's what we have here. The querent may know where he wants to go...but he doesn't have a clue how to get there. And he lacks the determination to find a way to get there.
Somehow, the energy of determination and direction must be unblocked. Otherwise, he's going to be driving about aimlessly and hopelessly. To the point where his additude is "what's the use?"
Another interpetation for this chariot which is blocked is that it's not moving; hence, we can predict car trouble. The querent wants to go somewhere, but the vehicle he would use to get there is out of commission, either literally (a car), or figuratively (a means to leave his job, his career, his relationship...etc).
3) Upsidedown: Turn the chariot upsidedown and no one is going anywhere. The wheels are in the air, the horses on their backs, the charioteer throw from the interior.
I know what you're thinking. And yes. Car accident
is an apt if frightening prediction for this one. At it's worst, the reversed Chariot is not merely about a loss of control and direction, but the complete loss of any means to get where you're going. You won't be leading anyone to victory, there's no fighting the war, let alone winning it. Anything inside (motivations, determination, energy) or outside of you is not working, not moving. The horses can't run and the wheels are spinning in the air.
You are stuck.