Do a search on "fusible" as in fusible link. Locate
my 1983 k20 that I'm in the process of restoring isn't getting any power. the interior lights won't go on and the volt meter isn't reading anything but my amber lights are still on. i cleaned the terminals, charged the batter and i even replaced the stater but still nothing
First check your two main battery cables, the positive to the starter and the ground cable to the engine (usually to the alternator bracket).
If they are good, do a search here for the word "fusible" - as in fusible link. Locate the fusible links and check that they are not blown. Your year truck should have 3 fusible links. Two are down near the starter solenoid. They are spliced into the red leads right above the connection to the B terminal - where the big black wire from the battery attaches:
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There is another right at the firewall junction block:
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