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Here's the relevant information...
'80 k10
- [Alternator is] getting really hot to the point I can't touch it. One even started smoking like crazy.
- I'm guessing i have a short somewhere but I can't find where.
- I replaced my battery cables and made sure i had clean connections and took my starter out and cleaned it. Every ground i can find I've cleaned up.
- When it happens my voltage drops and I smell hot electrical.
- I have a little thing that looks like a relay attached in my front fender with 4 wire going into it and one of them is broken the plastic off. I don't know what it is.
- My battery's only about a year old and all the cells are fine.
How intermittent are the symptoms? As Irish_Alley asked, is there any recognizable pattern as to when the symptoms occur?
Things you can do at home (don't shortcut or make any assumptions): Measure voltage at the #2 regulator (sense) terminal - it should measure constant B+ and match the voltage measured at the output post of the alternator. How does the output voltage at the alternator compare to the measured voltage at the battery with the engine running at ~2,000 RPM, using the same ground connection for both measurements? Connect the voltmeter negative lead to the battery positive post and the positive lead to the alternator output post with the engine at 2,000 RPM - what is the voltage reading? Connect the voltmeter positive lead to the battery negative post and the positive lead to the alternator case with the engine running at 2, 000 RPM - what is the voltage reading? Physically trace the charge lead from the alternator all the way back to the battery, inspecting closely for chafes and damaged insulation, especially around the back of the engine where the wire is hidden and where the positive battery cable crosses over the frame at the right front of the engine. Take a close look at the wires as they pass through the short steel conduit at the right rear corner of the engine next to the exhaust. Does the wiring show any evidence of heat stress such as brittle, discolored or distorted insulation? Repeat the process with the #2 regulator terminal sensing wire - where does the opposite end of the sensing wire connect? Check the three fusible links at the firewall junction block and the starter. Post a pic of the "relay with four wires."
Things to have performed by a professional: Have the battery properly load tested and a standard charging system test performed.