Truck burnt Fusable Link & more at the zone !
 

Question - Went to put a new battery in my 86 f150 5.0L efi, due to the old one having corrosion build fast around the positive side. The wire to the alternator near the solenoid sparked and smoked- burnt up bad. Been having electric issues - low battery after driving at highway speed, headlight switch burnt out, radio erratic volume until steering wheel turned or I hit a bump etcetera. Since I was stuck at the Zone I cut out the fusable link and hard wired the alternator direct. Truck started and ran fine, next morning had very sluggish start- Battery drained overnight ( same old battery- returned new one thinking it caused the short ) This Battery is less than 3 and super extreme with 800 + cranking amps, I charged it up and went to start the truck- solenoid makes a bizarre sound and brake light flashes. Tried Jumping the key on side of the solenoid and the starter clicks strong, but no cranking. I would blame the solenoid but recently had to cut a broken bolt out of the alternator with a torch possibly frying the internal diode (it's a 2g) . Also have a lot of water coming down the alternator bracket and rust issue where it should be grounding, this is from the water pump which probably needs a new gasket. Checked the bottom alternator harness- looks a bit dirty inside the female socket. The big issue- I can't afford to replace everything at once, Battery, alternator & Solenoid, but which one should I start with ? The Battery took a 5 1/2 hour charge at 10 amps, seems to have plenty of power and checks at 12.7 volts. I would like to figure out what the original short was and which part needs replacing, luckily the truck is at home and I can work on it. Any Response welcome thanks.