1994 Ford Escort Can't get heat

Ok, So, I'm used to working with fords in the cooling and heating department. I've got an escort that has 177,000 miles that isn't heating up. In the summer time, the AC running would allow me minimal cool air but would heavily heat my car up to a point that it would overheat. I was told that the relay fuse/switch needed to be replaced because escorts were known for burning these fuses out. I haven't replaced it now that it's winter time but I'm wondering if that is the reason that I can't get heat. The temperature gauge doesn't move, and it's fricking cold all the time. I actually have to turn on the defrost blowers in cold (which activates the A/C light) in order to see out the windshield to drive. I'm also experiencing puddles under my car after it's driven and then parked for a few days. I've checked the coolant reserve tank and refilled. I've pulled the radiator cap and filled the radiator, allowing it to burp several times, with no avail. Why can't I get heat?