Fried the Alternator, Replaced it, Still Not Recharging

[AOMills]

Long story short, I reinstalled my alternator and I didn't realize that the power wire was in contact with a bolt on the back of the alternator itself. A few miles down the road the truck bucked and then the voltage dropped to around 8-9 volts and the battery light came on. I drove up the road and pulled over before calling a tow.

I had the alternator tested. It was shot so I replaced it with a new reman unit. Now, the truck starts and runs like nothing is out of the ordinary and the battery light isn't on, but the voltage is still at 8-9 volts. The 60A ALT fuses looked good but I swapped them out to be sure; no effect.

I know I should pull the new alternator out and have that tested but what else should I check when I head to the garage again tomorrow?

 

[RonD]

Use a Volt meter and test the wires at the alternator

KEY OFF
Read battery first, that's "battery voltage" so lets says it is 12.5volts
Vehicle batteries should be 12.3v to 12.8v, under 12.3v means older battery and time to shop for a sale

Use Alternators metal case as the Ground for volt meter for these tests

Larger B+ wire(back of alternator) should have Battery Voltage, no need to disconnect it, if not full battery volts then fuse or fusible links are bad

Unplug the 3-wire connector
Yellow wire should have Battery voltage, if not fuse or fusible link is bad

White jumper wire should not be frayed, it is needed but can't be tested yet

Green wire should have 0 volts

Now turn KEY ON
Green wire should now have battery voltage, this is the Battery Light wire, and the ON/OFF switch for alternator.
If it has no volts with key on then fuse is blown


If all wires Test OK, reconnect 3 wire connector and start engine

ReTest B+ voltage using Alternator's case as ground, above 14volts is expected just after starting
If below Battery Voltage, then replace alternator

test voltage at battery, should be same 14+ volts, if not then one of the battery cables is bad or has corroded end


Charging systems with internal regulators are not at all complicated
Just 3 wires to test

 

[AOMills]

Thank you RonD. I ran through all of those steps and my failure is here...

Larger B+ wire(back of alternator) should have Battery Voltage, no need to disconnect it, if not full battery volts then fuse or fusible links are bad

I ripped open the conduit and everything and the fusible link was mush. Now to come up with a fix for this.

 

[RonD]

Just run new wire from B+, with new fusible links, it will go to Starter Relay(solenoid) Post where Battery's positive cable is connected

Some models around 1990 used two 60amp fuses instead of fusible links

Images here: http://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_charging_1991_1.JPG
http://www.therangerstation.com/tech_library/EDiagrams/files/Diagram_charging_1991_2.JPG

As shown in drawing you want to use two 14ga(gauge) fusible links, color doesn't matter, 14ga sets amp rating
And they both connect to at least a 10gauge wire that runs to B+
Or you can use two 12gauge wires, one on each fusible link that runs to B+

The Wire connected to a fusible link(or fuse) must be a larger gauge(smaller number) than the gauge or the amp rating of the fusible link, or fuse.

If amp rating for fusible link or fuse is 30amps then the wire used must be 40amp rating or the wire becomes the "fuse", lol, not a good thing