A heater control valve is simply a water valve which allows more or less water to circulate through the heater core, depending on how much the valve is opened.he coolant flows  through the heater core all the time.    Temperature is controlled by:    Temperature blend door-control how much air travels through  the heater core -   A small motor that controls the blend door-a rather common  failure point.
In 2002, Tyson fought for the world heavyweight title at the age of 35, losing by knockout to Lennox Lewis. Tyson retired from professional boxing in 2006, after being knocked out in consecutive matches against Danny Williams and Kevin McBride.
For other people named Mike Tyson, see Mike Tyson (disambiguation). Michael Gerard Mike Tyson (/ËtaÉªsÉn/; born June 30, 1966) is an American former professional boxer who competed from 1985 to 2005. He held the undisputed world heavyweight championship and holds the record as the youngest boxer to win the WBA, WBC, and IBF heavyweight titles at 20 years, 4 months, and 22 days old.