1995 Ford Escort Is it worth it to fix or should I sell it?

Hi, my 95 ford escort wagon is having more and more problems and I am trying to decide whether or not to sell it. I am having problems with something that tells the cooling fan when to switch on. The cooling fan does work because we were able to manually overide and turn it on. A friend of my dad who is a mechanic had it in his shop for a day but was unable to find the problem because the problem occurred right before I was moving away so he wasn't able to finish his diagnostic. I do know he replaced two sensors which control the cooling fan and that did not fix the problem. The thing is I have a lot of other problems with the car. The alignment is off and it needs new tires. The drivers side automatic seat belt motor is broken so I pulled the fuse on it so it stopped making noise trying to move the belt. I could probably fix that by going to the local pick n pull and putting it in myself. Another problem is when the doors are open it always makes a beeping sound like I left the keys in the ignition or the lights are on when that is not the case. My stereo and cigarette lighter are wired directly to the battery with an on and off switch because their wires connected to the ignition went bad and I didn't want to try and figure out which wire was which. So there are a lot of little issues which add up and one major issue which is the cooling fan. The car runs and I can take it to work because my commute is all highway and no traffic so I move fast enough that it stays cool but that is something that really devalues the car.

Anyway the tires really need to be replaced because they are really bald and one is flat right now. I am wondering if it is worth it to even put any more money into the car or if I should just try and sell it for what I can get for it? If I were to sell the car to someone who knows how to fix the problems what would it be worth with those issues? It does still run and the mileage is only 90,000. Thanks.