83 k20 plow truck not charging
 

I just got a K20 plow truck with a diesel 6.2. What does it mean if the red wire on the back of the alternator is putting out 14.7 volts but it isn't reaching the battery?

Also the truck has several other electrical issues in case they are related: Headlights intermittent; temp, oil, and alt gauges not working.

I greatly appreciate any help.

Jeff

Re: 83 k20 plow truck not charging
 

Hi Jeff,

All gauges on dash not working sounds like a blown fuse.

If the alt is putting out 14.7v, try testing for juice @ the electrical junction up on the firewall while the engine is running. There's a fuseable link that might be bad or just needs a little bulb grease to make a good connection.

Same thing happended to me lately. I had just rebuilt my alt. & a week later it stopped charging the batteries but still put out 14.7vt. After some digging, I found an aluminium butt connector hiding in the line (behind the engine), going from the starter, up to the fuseable link on the firewall. It was poorly crimped & had melted from the 96 amps the new alt was putting out. (A winch draws alotta amps!)


Same goes for the headlights. If they're going out (or flickering) at the same time, either a dirty/bad fuse, a weak ground, or possibly a poor connection @ the headlight switch under the dash.

When I'm tracking down electrical issues, I always start with the easiest fixes first.

Hope the above helps...

FtP

Re: 83 k20 plow truck not charging
 

That helps quite a bit. Thank you!

Looks like i'll be learning about fusible links this weekend.

Re: 83 k20 plow truck not charging
 

I traced the red wire from the alternator to the starter. There are 3 wires with fusible links at the starter - I'm told they are the alternator, headlights and ignition. The wires were pretty corroded, so that could have been my problem. I've been advised to route those 3 wires to a junction block on the firewall instead where they can get power directly from a cable run from the battery.

Bigger fish to fry at the moment, though. I discovered that 1 of the starter bolts was sheared off, probably because the starter bracket was missing. Hope i can get the remains of that bolt backed out of there.

Jeff