Nissan Repair: 95 altima transmission solenoid, nissan altima, solenoid valve

Question
hi! I have a '95 nissan altima (automatic) with low mileage (73K). I really love this car and want to rescue it, but I'm poor,

Its stuck in 3rd gear, I'm told this is some kind of safety mechanism it goes into when it has a problem. The diagnosis code that comes up is Shift Solenoid Valve ‘‘A’’.

The car has had some electrical spasms in the past. About a month before the car went into perma-third I lost the dash lights and tail lights. Upon replacing the fuse, it caught fire and melted, so I guess that  means I have a short somewhere. The computer also brings up the knock sensor code (i thought this was not worth $).

1. Do you think the electrical problem could be related? it happened a month or maybe two before the tran problem so it would have to have triggered some other short(?)
2. Is that solenoid thingy on the outside or inside of the transmission, and if its broken what do you think it would cost?
3. They want me to pay money to do "further diagnosis" so I'm wanting to know if that would be worth it. if the verdict is "this will cost more than you make in two weeks" then its not worth it. I make 750$ in two weeks (impoverished grad student). I might be able to swing 850-900.

Answer
Hi Shaina,

The solenoid thingie is located inside the transmission. The repair should run $200-$250 or there abouts. If you don't fix it quickly though, you will wreck the transmission and you don't want to know how much that costs! Trying to diagnose electrical problems in this forum are about as much fun as a trip to the dentist. If you have a Cottman Transmission near you take it to them. They will do a diagnosis for you for FREE! cottman.com