1990 trans sport- help please

Hello. First off, just bought a used 1990 Trans sport SE.. have had it a total of 1 wk now. Warrenty only works for engine.. engine works fine! Of course. A few problems maybe some of you nice folks could help me with.. 1) my speedometer just went tonight.. nothing reads on it at all now. Can I fix this or am I looking at huge money? 2) My headlights don't work. I have running lights that are always on. Brights work but just the headlights themselves don't. Is this a short or am I screwed on this too? 3) My back hatch lock doesn't lock with automatic locks or with the key, is there a quick fix? 4) (Only asking this because it is summer now, usually wouldnt care) A/C- it works, it blows out faster as I turn up the speed, but it doesn't feel cold, just cool.. is this just because it is a van and takes a long time compared to a car or is something wrong.
And yes I am a girl, I honestly know nothing about cars, let alone vans, but I have sat here for hours and I just spent my savings in this van, and can't take it back.. I gonna fix her if anyone can help me out.
Thanks bundles in advance
Sherry

Most of your problems could be something relatively simple like a disconnected connection, or something more complex.

1.) My first guess would be the speed sensor either went south or came unplugged, but a wire could have broken or the gauge gone south as well.

2.) I'd be suspect to a bad switch if the DRL and hi beams work, but the regular ones don't.

3.) locking linkage probably has broken or a pushrod has popped off or bent. The only way to really tell for sure would be to try to get access to it to see what's not moving.

4.) Your AC may needs a recharge. Remember your vehicle is 15+ years old. Since you say you can get cool air, just not cold, that is a good sign that you don't have a large leak. Your evaporator coils also could be dirty and need to be cleaned.

Thank you so much. I kept reading and reading on here to try to find if someone else asked the same things you saved me more hours of sitting here. Sherry

The mixer door in the heating/AC system diverts the air (that went through the a/c evaporator) around and away from the heater core so the already cooled air does not get heated again (when you put the temperature control to the full cold position). However, it can happen that it does not return fully to the "bypass" position for several reasons. !st, some stray material (leaves) has invaded the system and prevents the trap to move full closed. 2nd, this trap is moved by a small electric system that "senses" where you want the trap to be and sometimes, if moved slowly, it will not go fully to the end position so I move the control to full heat..wait just a few seconds, and then move it in one shot to full cold, and it helps. Finally, the motor drive can be worn out and will not be able to go to full cold.
This is in addition to the possibilities mentioned before and yes, there is a long story on this forum of fouled and clogged evaporators that just return to high performance after thorough cleaning, but this is generally accompanied by poor airflow.