Melted alternator cable

Recently replaced alternator with an OEM, about 2 months ago.

This week my charging light came on, and upon inspection, I found a melted cable terminal. Speaking to the dealership, they are stating a part number of:
82121-04490
which is apparently a complete engine wiring harness replacement, running 1800 + labor.

I don't even know if the replacement is worth it because the alternator might have caused the issue in the first place. Dealer doesn't seem to think it's repairable. Am I SOL on this? On a 14 y.o. truck...may be time to throw in the towel.

Any idea what could have caused this with a new alternator?

 

When you installed the new alternator did you appropriately observe the original stack of washers, isolator washers, lock washers, and nut torque?

Are you running an AGM battery and or a voltage booster?

Consider @deanosaurus 's "Big Three" (five) wiring upgrade, definitely cheaper and better than factory.

 

Either someone forgot to tighten the nut on the alternator or there was corrosion on it causing a bad connection which generated alot of heat.
If the wire itself isn't damaged all that needs to be done is to crimp/solder a new ring terminal on the wire and replace the alternator if it's damaged.

 

That's the plastic/rubber cap on top of the terminal. The cap itself is a $6 part: https://parts.toyota.com/p/Toyota_2...INAL-TERMINAL---NO-1/62971425/8282308010.html but you have to open it up and see the extent of the damage.

 

‘Complete wire harness? Shotgun school of auto mechanics. Do you have the capability to checkout the rest of the wire harness? If not, you are at their (or some mechanic’s) mercy.

 

Dealer is either an idiot or loves to rip people off. If you can’t do it have any complement electrical person replace the terminal lug and any portion of the wire if it’s hardened/damaged. Someone above posted a link to the boot to cover the terminal. Also check out the alternator to make sure the poor connection causing the overheating was external and not internal.

 

FTFY.

 

Update: got the harness off. More pics. Bottom line: would the alternator be ruined from overheat or is this fixable (wire brush, contact cleaner, etc)?

 

Clean it up a little first and then you can get a better look at what - if any - real damage has been done. My first impression is that it looks fixable

 

I'm no electron expert but I'll try to explain, anyone feel free to correct me.

Think of the flow of electricity like the flow of water. If there's a restriction, say 1" pipe to 1/2" back to 1". With electricity, a restriction would be 10 strands of wire, to 5 strands, back to 10 strands. The 5 strands of wire are gonna get hot.

 

It's like the connection at the blower motor resistor pins. A little bit of resistance creates heat, the heat makes shit get crispy and melted, the melted shit adds further resistance and the whole thing snowballs..

You could try cleaning it really good, but don't be surprised if it keeps getting smoked

Every time I've seen a alternator with a melted connection like that I always recommend replacing both the cable and alternator. That's the only way I can guarantee it won't come back

 

I would also replace the alternator and the terminal on the cable.

 

Looking at how far back that insulation melted, I'd splice back far to good wire/insulation. Perhaps one of the diodes failed "on" and your alternator caused the high current. I've seen it happen on various voltage regulator from reputable companies such as bassler, denso, and others. I'd take the alternator out and have it load tested before connecting a repaired cable and seeing another smoke show.

 

complete engine harness? the charge harness is seperate from the engine harness.

https://parts.toyota.com/p/Toyota_2...attery-Cable-Harness/63169479/8212204320.html

its an fairly easy harness to remove. repair is not out of question. but the price they gave you was for the ENTIRE engine harness... that would literally fix nothing

 

I've seen this a few times.

Installation error, the cable wasn't seated.

I've repaired this before with a part store end to the alternator terminal, using a lock washer. Never saw it again.

 

I agree. When you do electrical repairs daily as I do, it’s sometimes hard to imagine this kind of approach doesn’t occur to more folks. Not only is it acceptable, it’s far easier and more economical.

 

If a dealer thinks he can charge me $1800 for a whole harness rather than a terminal lug and a cable I can replace for under $100 myself then one of us is an idiot and it’s not me lol. Yep, rip off, that’s a job for an electrician not a dealer who has zero electrical skills.

 

I don't think they intentionally misquoted. Probably an inexperienced parts guy that didn't know how to look it up.

I incorrectly assumed the cable was part of the harness, Empty lord pointed out the separate part number

 

If they get one out of every 20 customers on that job, they're in the black