Disconnect the A/C lines sticking out of the firewall beneath the hood. They are quick disconnect fittings and require a disconnection too that is fairly cheap and available at any auto parts store.
Remove the 2 (7mm) screws holding the glove box in.
Remove the glove box.
Take out the 4 (7mm) screws in the plastic that is closest to the passengers door.
Remove the 3 screws (10mm) that hold the metal brace in that was behind the plastic previous removed.
Remove that metal bar going across the bottom of where the glove box used to be. That has 2 (10mm) screws holding it on.
Remove the wire harnesses that are attached to the blower motor. Optional: remove passenger kick panel.
Remove the 3 (10mm) nuts that are holding the blower box in place. 1 is in the middle of the passengers side firewall at the bottom of the box, the second is to the right of that one about a foot over and the 3rd is in the middle of the firewall right behind the cable that controls the outside/inside air.
Now remove the vent that goes to the windshield.
Look to the left of the box you are removing. Then yank out the evaporator until it comes out, it's strong enough to not worry about breaking anything during removal. Don't forget to unhook your a/c lines on the inside the engine bay prior to pulling the box out.
Install the replacement core in reverse order.
Also see
Ford Escort & ZX2 section for the entire index of all Ford Escort and ZX2 related articles.
Seems to me you may have two separate issues, but maybe not. Could it be that leaves, a mouse, or other debris has gotten into the fan box blocking the air flow and finally jamming the fan? It maybe possible to remove some parts under the hood to gain access to the air intake and use a shop vac to get the debris out. You may still have to replace the fan fuse, motor, or resistor as well. Also check that the radiator is properly filled, as low coolant can cause the heater to work poorly.
check your fuses ,if they are good track down the hot wire leading to your switch ,if you have power going into switch ,but not coming out going to your headlights, it might be the switch went bad,also check your ground connections
Sorry to say, But doing that is the fastest way to burn up the computer. All of them. But you could luck out . Try replacing the ignition module first.