Vehicle Animation on Key Press

How would I get an animation thread to work every time I press a key for a vehicle? Something along the lines of the Wave cell animation for the player. What happens currently is the animation will play the first time I press the key, but then will not play again. I can add it to another thread and it will play again, but I can't get a thread to reset. Is there something I'm missing, or do I have to go rip the code from the player and add it into vehicles?