see photos below for the key on the diagram for the gauge.

when I restarted it, the pos-pos was steady at 0.48 V (neg-neg was steady at 0.02V) and then I checked from the junction block where the fusible link attaches to a puncture inside of wire D right before it attaches to the fusible link. Basically on either side of the fusible link. It measured steady at 0.14V. What do you make of it?

both red wires out of the alternator are the same gauge. The other one (J) plugs in with a clip (also has a small brown wire).

all the gauges of the wire at the junction block are the same size as D which I am assuming is 12G.

 

Your right,12gauge from the alternator to the junction block, surprised its not 10 like the run from the block down to the starter. Maybe measure all the drops from the alternator to the battery to make sure you don’t have another bad link or crappy connector. that temp link drop may get better after a proper permanent repair. 0.14v at say 40 amps charging is 5 watts of heat dissipation at that link.

George

 

should I turn that fusible link into the permanent repair at this time?

also, can you diagram where I would be testing all those drops from the alternator to the battery?

 

I would test the voltage drops first and if it’s spread evenly around with no other problems detected then make the repair permanent.





George

 

sorry for the delay, I have been working out of town for a few days.

1-2 measured 0.17V which to me is very odd since it is a continuous wire.
2-3 measured 0.12V, then I retested it and it was 0.17V. The other day I was getting 0.14V

i will try to get the rest of them tomorrow. At my age it is hard to get under the vehicle without twisting something in my neck or back. I will try to get my teen to help.

 

Could that splice be corroded between D And B?

George

 

No, the splice is gone. I have B, D and E all joined as one temporarily. I used wire strippers to expose fresh wire on each one. That is where I measured point 2 (your diagram)

 

AT this point I think you can skip crawling under the truck. The voltage drop for the rest of the run is about the same as the first two segments so there should be nothing dramatic going on there. Your total voltage drop does meet the spec.


George

 

does that mean the problem is fixed? Well, fixed as soon as I make permanent the connection between B D and E?

and if so, does that reconcile with my initial problem: with the key out of the car, I first connected the positive battery cable and as soon as I connected the battery cable, the fusible link started smoking?

 

We never found the smoking gun, the cause for the link to blow. It should, in theory be a short to ground in the tens of amps. I expected us to find it when you rigged up the initial fused connection but the problem did not repeat. Maybe it was the trailer module or a short that was relieved from moving wires around. I thought it was going to be the alternator but it tested ok. Intermittent failure? I wanted to find and correct the cause with you, that’s the right way to go about this but when you first reconnected everything and the fuses didn’t blow that left us with no clues to chase. Can a 16 gauge corroded link blow from the standby current of a truck in the off position? Maybe if the standby current is too high because a an unresolved parasitic draw problem. You don’t have an amp clamp meter to easily chase that. We could go through the parasitic draw process with an in-line a meter to check.


George