It is located right on the charcoal canister that is in front of the muffler under the passenger side rear axle.
Assuming this is a 4.3L engine, the canister purge valve is located on top of the engine on the drivers side towards the back.
There is no EGR valve on the 2002 4.3L (code W)
Horn valve? Please give more info.
under the master cylinder.
It doesn't have one.
No.
"EVAP System Flow During Non Purge" Most likely the purge solenoid is stuck open. If it is the 4.3 engine the purge solenoid is located on the right side of the intake manifold.
The 1994 S10 has a fuel pressure regulator located in the throttle body.
"Where is the heater controll valve on a 2001 Chevy S-10 controll Valve? "
No.
No, it does not.