you have to take the alternator off and put the one you bought from the store on and start it and if it freezes you have to take it back
I did this myself a few weeks ago. I also strongly recommend using a spray cleaner and rags or a hose to clean the gunk and grease off the Alt. It's shot, yah don't have to worry about getting the insides dirty! Besides, when yah take it back and they open the box to look at it you can cheekily say yah cleaned it off for them! 1: Disconnect negative terminal on battery-this is a rule or you'll suffer a blown diode in the alt. when you plug one of the wires back in. Then you'll have $90 bucks of scrap metal. :-) 2: Put a 3/8" breaker bar or ratchet into the square hole on the tensioner and pull to front of car to loosen and remove belt or shove out of way then ease it back. 3: Remove the a/c hose bracket from the top of Alt. bracket. Tip: You may need to also unbolt the a/c hoses from the strut tower to wiggle them around for more room. 4: disconnect the electrical wires from the Alt. Two use those stupid little snap connectors, use a small screwdiver and carefully ease them off. The main one uses a small nut, that's another reason to disconnect the battery since that's a positive connection! :-) 5: (Very Important) Unbolt the Power Steering reservoir and try to shove it aside a few inches. I didn't do this, bolts were extremly rusty and afraid of breaking them I skipped this step. It was the cause of much cursing and swearing later since the wiggle room was then extremly limited, almost impossible. It was 50 degrees out tho, so that kinda kept me warm for awhile....:-) 6: Loosen, then remove the top and bottom mounting bolts. The bottom fastener has a sliding nut built into the Alt. bracket, I think mine was stuck in place so was the cause for some warm up cursing before trying to actually get the Alt. to slip up and out. :-) You may want something handy to pry the Alt. up and out. 7: If your lucky then you can grab the A/C hoses with your right hand and ease them aside as you use your left hand on the pulley to lift the Alt. up and out like that stupid picture in the haynes book. If not, your gonna be swearing a lot, especially if you didn't clean the gunk off and yah can't get a grip on the darn thing. :-) 8: Clean your hands off, your gonna need a break anyways. :-) 9: Now you can re-install everything in reverse order or any order you want, just connect the battery terminal last.
OOps forgot to add, this is for a 93 escort with 1,9 Liter engine. According to Haynes, the 1.8L alt. is mounted lower and after loosening bolts yah need to jack car up and remove a splash shield to remove the lower bolt, then remove Alt. 2.0L engines (coupe) need the coolant reservoir removed for wiggle room. 2.0L wagons and sedans, you need to free the Oxygen Sensor wiring harness from it's retainer on mounting bracket and unbolt power steering and A/C hose brackets from top of Alt. bracket, then remove mounting bolts.
In 5: above, in addition to unbolting the power steering reservoir, in the '94 Escort you should also remove the radiator overflow tank. Located to the left of the power steering reservoir, Two bolts attache it to the firewall. Removing the radiator overflow tank lets you move the power steering reservoir completely out of the way, allowing the alternator to be easily removed and then re-installed.