I am wondering if someone can help me with a circuit. Its for a set of retractable running boards that are installed on a vehicle. The running boards have to go down when the door switch grounds, and they have to go back up when the door switch goes open. But there is one catch. There are no limit switches. The polarity of the motor is easy enough to change, but without limit switches, the circuit will have to shut off and stay off when the amperage reaches about 15 amps. The circuit will have to turn on again when the door switch changes state again. In either case, the motor will have to stay off until the state changes again. I would suggest that the initial amperage may be higher, so a timer circuit may have to be used to keep it on for the initial amp ramp up of the motor.
Please let me know if you have a solution to this. Motor run at 2 amps when running boards are open, and about 4 amps to pull them back in.