94 LeBaron questions.....multiple

First, I got this car used, apparently from a teenage girl. Just judging by the things that were in the car when I picked it up. One must understand, I got this car in trade for a 500 dollar VW. So any money I put into it is fine, really. Not a huge loss. It's much better than buying something newer and still putting money into it.

Now, the first issue is the speedo and odo not working. When I got the car, the trip reset would not work. I pulled it apart and fixed that part, but couldn't see any problem with the gearing inside the speed cluster. So my question for the forums is, does this seem like a speed sensor problem, or is there another issue inside the cluster that I can't see.

Second question. Is it normal for the parking brake wire to melt and take all the wires under the driver seat with it? My top was malfunctioning and diag revealed this was the case on my car.

Third, the middle mirror wires have no power. EVER. Could this be caused by the melted wires I found? Where does the power for the lighted mirror come from physically?

Also, where is the air charge sensor located? I believe my mileage problem is related to the fact that this sensor is missing. completely, just gone.

Theres probably more I'm forgetting, I'll probably be back to add more, but if you would help me with these starter questions, I would be most appreciative.