What is the role of single wire connection to power steering pump?

THE ANSWER TO WHAT NEISHA HAS ASKED IS WRONG.She has asked why is there a single wire connected to Esteem carburettor power steering pump which is hydraulic and is driven by the belt of the engine main pully. There is NO ECM to give any signal. There is NO motor in the power steering pump. So what for has this wire connected?
If some one can throw light please write
Thanks

shailendra
April 2009

This from Wikipedia mentions Suzuki...

"Electro-hydraulic power steering systems, sometimes abbreviated EHPS, and also sometimes called "hybrid" systems, use the same hydraulic assist technology as standard systems, but the hydraulic pressure is provided by a pump driven by an electric motor instead of being belt-driven by the engine. These systems can be found in some cars by Ford, Volkswagen, Audi, Peugeot, Citroen, SEAT, Skoda, Suzuki, Opel, MINI, Toyota, and Mazda."

So the wire probably carries power to the hydraulic pump the negative return being through the chassis. A relay likely controls power to the pump.

Peccavi
April 2009