Please help problems with 87 suburban

[danomano]

We just got a 87 suburban motor and trans strong. But here are some problems that are diving me crazy.
1. either it has a short somewhere or altenator is bad. I had battery and alt tested at autozone and alt came out good battery was 11.5 volts replaced but checked volt when running and only get 13. We drove to parents house and back then truck would not start. Also headlights were dim.
2. for some reason the gauge fuse keeps blowing. Does not blow right way just after time (like 5 minutes or less) it goes out. I am thining temperature sender?
3. drivers door lock latch sticks on the inside and jams the door. Now this only happens when you lock the door then close it. tried spraying wd-40 on it but it came back twice. I have also remove the electric lock so I know it not that.
4. is the knock sensor needed or the 4 prong connector for the 700r needed? Someone who ever changed the starter broke the connector on the knock sensor and it is just hanging down. The Transmission conncetor is also broke due to someone replacing the transmission and not un hooking it.