1998 Chevy S10 heating problem

sounds like a fuse to me

your gonna have to remove actuator and manually move door to see it that helps.
did you get right actuator? there are 2, 1 manual and 1 auto climate controls. maybe reduce file size or change format? Take a look
www.xcardiag.com

under the hood there may be a fuseable link in the wire or in the relay switch box

p0171-System Adaptive Fuel Too Lean

p0401-EGR

p0452-EVAP Fuel Tank Pressure Sensor Low Input

p0131-Upstream Heated 02 Sensor Circuit

Hope That Helps.

please change your thermostat,I hope that help you it sounds like it stuck open

You need to check your coolant level first. If it is low you have a coolant leak. No hot coolant=No heat

When you say the heat doesn't work are you meaning the fan doesn't blow out hot air or just doesn't blow out any air? if it blows cold air sometimes when you have the heat on then it could be poor circulation through your radiator or a weak water pump. make sure your radiator is clean on the inside, not too corroded or nasty inside. You can buy a radiator flush thing from wal-mart or any auto parts store. See if it helps.

Well FOR THE FIRST PROBLEM YOU PROBABLY NEED TO REPLACE THE THERMOSTAT IT IS MORE THAN LIKELY CLOSED SHUT NOT LETTING COOLANT INTO THE BLOCK TO CIRCULATE THE HEATED COOLANT 2ND THE UNIT IN WHICH CONTROLS THE TEMPERATURE OF THE INSIDE OF THE VEHICLE IS OR MAY BE BAD I WOULD START WITH THE THERMOSTAT FIRST BEING THIS IS USUALLY A MORE COST AFFECTIVE SOLUTION GOOD LUCK!

remove the heater hoses at heater core and backflush heater core with a water hose it is clogged

If you are certain there is no air in the coolant system, then there is a chance that the blend door motor is not working or the heater control assembly is bad. since you have replaced your own heater core you probably noticed the the doors inside the heater core housing. One of those doors is controlled by the "hot/cold" knob. The motor on that door could bad.