mrtoronadoman

well, here’s the cable running from positive battery post to the alt. That explains a lot.

Vintage Chief

Toasty

Dynoking

Can anyone explain the function and location of the “ALT/GEN (charge light) sensor switch”?

Sugar Bear

I believe the burned section is a fusible link, a wire intentionally placed and designed to melt and interrupt the circuit to protect the rest of the wiring and the entire car from igniting. Replace it with the proper fusible link wire/material to afford future protection in case of an electrical overload.

If I'm wrong and that isn't a fusible link someone please jump in, thanks!

Vintage Chief

Agree 100% - that is a fusible link.

Vintage Chief

Point taken. Not 100% on this, in lieu of no CSM, no wiring diagram & no member assistance (thus far), I believe there exists an in-line resistor (calling it a ALT/GEN sensor switch) somewhere in the electrical circuit - I suspect; obviously, I can't validate this w/o a wiring diagram. On certain other vehicles, at some point in some electrical systems I believe manufacturers inserted a resistor to "sense" a state of charging condition. A wiring diagram would be nice.

Vintage Chief

At this point it would be nice to see an electrical wiring diagram from one of these two manuals as pointed out by rocketraider. It should certainly demonstrate the wire gauge for the fusible link.

mrtoronadoman

, After taking it apart, it appears to be a smaller gauge wire than the long red one with what looks like a butt connector in the middle. I’m at work now and was thinking of buying some wire while I’m here so I can put it all together when I get home. Or without knowing the gauge, the best I can do is get something that I can visibly see is smaller than the red wire.

Sugar Bear

Using the wrong wire is a mistake, it removes the protection afforded by the correct fusible link. Research this first but I think fusible links are generally 2 wire sizes smaller than that which they are protecting. Again do your homework.

Vintage Chief

I believe automotive industry standard is 4 gauges smaller than the wire the fusible link is protecting. Albeit, a 14 gauge wire would be protected by an 18 gauge wire. NOTE: Critically important is the correct length. The fusible link wire needs to be the exact same length as the one you are removing. Without a wiring diagram it's tough to say what the gauge is of the red wire the black fusible link wire is protecting; although, if you can visually witness a gauge number on the longer red wire, you'd be able to arrive at the correct gauge of the fusible link wire. As Sugar Bear has suggested, do some homework on the correct sizing of a fusible link. Again, ensure the fusible link wire is of the exact same length, as well.

Finally, I don't believe we know with certainty what caused this fusible link to lose its integrity; so, there may still exist some work ahead - maybe, or maybe not. You can continue troubleshooting if you so desire. It would "appear" the fusible link did not BURN and it did NOT completely lose its integrity. It doesn't appear to have been burned through & apparently it still maintained some (minimal) integrity (I guess) since the car started. However, this thread began with suggestions regarding two fusible links located near the starter solenoid. Is this particular fusible link a different fusible link than depicted in the image(s) above located near the starter solenoid - indicating this is at least a third fusible link? Would be nice if someone had a wiring diagram, eh?

Vintage Chief

Upon further evaluation of that fusible link wire, it appears someone else has had an issue with that particular fusible link since it appears to be covered in handyman electrical tape which is NOT correct for ANY fusible link.

EDIT: Oh hell - maybe the fusible link wire "is" broken - I don't know hard to see clearly. Maybe that's why the ALT/GEN (charge light) is ON? Anyone have a wiring diagram?

mrtoronadoman

So I’ve been able to figure out that the red portion is indeed a 10G wire. That is the spec on the AC Delco replacement part. Also compared mine to some 10G wire here in-store. Also confirmed automotive standard is 4 smaller than the main wire and 3-4inches in length. I have some 14 gauge set aside as well.

Vintage Chief

Grab a full-circle enclosed "O" end-terminal to replace that open "C" terminal at the alternator, as well.

Vintage Chief

And, once you get the wiring in order, measure your battery voltage at the battery w/ the car running to validate the alternator is charging correctly. Post #40

rocketraider

Go to the parts store and get a PROPER fusible link to replace the burned one. Can't overemphasize how important that is. Fusible link wire IS different from standard automotive wiring and the things are readily available.

The fusible link did its job. No need of compromising it.

Fun71

You work at an auto parts store, right? Your store should sell fusible links.

Dynoking

^^^THIS! ^^^
The fusible link is not just a smaller gauge wire. Hypalon rubber is used for insulation. It will melt rather than start a flame. Repair literature should be consulted to determine the proper replacement gauge.

Vintage Chief

Agree. It's the insulation protecting the fusible link wire which is important. Very good point.

Vintage Chief

Although, I don't believe Hypalon is manufactured any longer. Current wire insulation is made from Chlorosulfonated Polyethylene Rubber (CSM) so I'd suspect a fusible link would be made of CSM.

mrtoronadoman

For clarification, The wire I used was 14 ga “fusible link wire”. Also replaced the “C” connector with an “O”. Battery tests 14.6v when running, charge light is off. Unrelated but was also changing plugs during this project. P/O had Bosch Platinum (0.040”) installed and I went to AC Delco Copper (0.060”) and WOW what a difference. Runs like a new car.

rocketraider

Glad the issue is resolved and no permanent damage.

My experience is Oldsmobile engines don't much like Bosch spark plugs. None of mine ever ran that well with them, and several friends had the same experience.

Vintage Chief

Good work.

Dynoking

X2. AC Delco for GM engines.