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.
Evander Holyfield vs. Mike Tyson II. Evander Holyfield vs. Mike Tyson II, billed as The Sound and the Fury and afterwards infamously referred to as The Bite Fight, was a professional boxing match contested on June 28, 1997 for the WBA Heavyweight Championship. It achieved notoriety as one of the most bizarre fights in boxing history, after Tyson bit off part of Holyfield's ear.