Charging System Problem

GoneMuddin1

Well-Known Member
Joined
Jul 3, 2006
Location
Concord
I've got a new problem that I'venever run across before with my '81 K30 not charging correctly.

I've got 12.5 volts at the battery while the truck is running, 12.5 volts at the red wire in the connector at all times, 0 volts at the brown wire with the ignition off, 17 volts at the brown wire with the engine running, and 52 volts at the alternator output.

I've checked for blown fuses, but all in the panel are intact.

Hopefully someone has run across this before.

Brandon
 
burned fusible link at the starter

the hot lead off the alt goes into loom to tube runs down side of engine/trans next to exhaust manifold, there are 2 or 3 fusible links coming off the battery lug of the starter.one of those is probably toast.

Pull your Alt and have it bench tested to be sure the internal regular isn't fryed ( causing over voltage and cooking the link) do this BEFORE you make repairs to the links or you'll fry it again.

you used to be able to by just the fusible link repair harness, has the eyelet and a yellow crimp connector, a good parts guy will know what you're looking for.

12.5 volt off the battery is normal, not sure where your's getting 17v, but thats too high for anything running or not, engine running alt charging properly voltage shouldn't get over 14.5-14.8 tops even at rpm. 52v is concerning, tells me the regulator is gone or your meter isn't working right.
 
I'll pull it apart and check the links.

I was concerned to see the 17 volts, let alone the 52 volts. I know the meter isn't bad, since i got a good little shock off the alternator when I went to disconect the output after shutting the engine off.

This truck has had some serious jacklegs working on it over the years, and I have been slowly rewiring all of the "repairs".
 
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