2001 explorer sport trac fusebox/ wiring diagram

[cinnamonsmooth]

I turn on the heater and it blows cold air. Is it a fuse? If so, location? Where to start troubleshooting?

 

[MidnightRebel07]

Could be a number of things but the fuse is probably not it. I'd look at the heater control valve and the heater core to make sure the lines aren't clogged to it. the heater control valve is on the right side of the motor just behind the belt tensioner. It's in line with the heater hoses going from the heater core and the water pump.