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.

[danomano]

So I disconnected the negitive while it was running and it died. So I check the positve for a current draw and was only getting 10mamps.
So I replaced the altenator and fired it up got only 12.3 volts? Then tried to start again and it would not start. Had to jump it. This time it ran and I got 14.5 volts. Thinking it fixed. Replaced fuse for gauge and they were working. Turned it on/off about 10 times no problem. Drove it around for twenty minutes with everything running okay still. Have wife drive it to mall and she gets about 1/2 there and tells me the fuse blew again and the lights are beeping ( like when you leave them on after turning the truck off). So when it home I start it and check the volts and it is only 11.9 while running.
I think it time to put this beast to rest in a junkyard.

[tobiahr]

sounds like you may have a short/open in the ignition...check for damage on the lower portion of the steering column

[rcbildr]

There are fusible links to check too. IIRC my 84 Suburban had one just off the alternator and there is one down by the starter. They are connected to the system with those crimp on connectors...if there is any corrosion in those connectors it will mess with you. Also check the junction block on the firewall...it's up above the driver side valve cover...at least that's where it is on my 85 suburban. There were a couple more of those crimp on connectors that I had to replace. Hope this helps.