The steering wheel robot is the steering wheel of a Cadillac Escalade, transformed into a creepy Transformer with spider-like limbs. It was given life when Sam Witwicky accidentally dropped the All Spark. It seems to like its owner and hugs her face.
When Sam accidentally drops the All Spark while fleeing through the streets of Mission City, he bumps into a woman's car. She is angry, and believes he dented her car. This is forgotten as the steering wheel of her car develops spider-like legs, wrenches itself free from the steering column, and clamps itself onto her face, hugging her head while she lets out muffled screams. It is unknown if the whole car was affected by the dropped All Spark or just the steering wheel alone, and whether the woman survived the ominous face-hugging steering wheel.
It is known, however, that it shut her up quite nicely.
After the battle, the Autobots and Lennox's soldiers locate the steering wheel bot which Ironhide blows to pieces.