I am trying to figure out why I dont have heat in my tahoe and have been replacing parts and now I am at the heater control valve but dont know its location, so far I have changed my blend door actuator. I have rear heat but it takes a while to get hot so I figured I will change the heater control valve now so if anyone could point me to its location it would be appreciated! if that doesnt work I am gonna replace the thermostat!