According to Sunset Western Garden Book, beans need full sun to grow. Full sun means at least six hours of sunlight per day. Plant bean seeds as soon as the soil is warm, in full sun and in good soil. Beans come in two types--pole beans and bush beans.
Determine Sun Exposure
In early summer when the ground has warmed, take a day to record the amount of sunlight in your garden. From dawn until dusk, every hour record whether your garden is in full sun, partial shade or shade. At the minimum, record whether the garden is in full sun at midday.
Plant your Beans
Pick the sunniest spot to grow your beans. Pole beans take up the least amount of ground. Pole beans will grow towards the sun. Bush beans can be grown in a container. Place the container where it will receive the most sun.
According to Duane Newcomb in "Growing Vegetables The Big Yield Small Space Way," if insufficient sunlight is your problem, don't give up. you can augment your natural light with a reflector panel or wall. Make reflector panels by putting aluminum foil on a large piece of cardboard or plywood. Set the panel on the north, east or west side of your garden.