Alternator Wire Overheating

You definitely need some help, but your description doesn't provide much help. But strange things like this are usually caused by poor connections. Check the place where it glowed and make sure the connection is clean (this is a direct connection to the battery, disconnect the battery first). Also, be careful with that connector. It can be broken if overtightened. Then check the grounds (engine mainly, but also to the car frame).

===== Let me guess, .. you did not use a Toyota remanufactured alternator. The voltage regulator is solid state and inside the alternator. The quality of aftermarket "rebuilt" alternators can be so poor that I stopped using them long ago. Once had a generator replaced something like twelve times under warranty, but I was making 200 miles trips at the time and it was inconvenient even though replaced without charge. After switching to the factory unit the problem vanished never to return. Similar experience with starters. While they may cost more, factory remanufactured units are like new because all parts subject to wear are replaced with original quality. Rebuilt just means they get it working and repaint the exterior. For future reference, generally the only thing you need to do to keep a Denso alternator working is replace the brush assembly before

There are people other than Toyota who can put out a quality remanufactured alternator, BUT your local Autozone may not be one of them.

The wire you speak of, is carrying too much current. If the alt is providing normal output to the battery as the voltage readings atest to, then it sounds like there is a poor connection which is causing the bulk of current to use the smaller wire. It would help if you could say which wire is overheating, or whether its in the +ve line out, the "IND" line, interference suppression or an earth. A glowing wire is not all that safe in an engine bay. Dont leave it like this.

Jason

Forgive my lack to technical lingo...what can I tell you is that its the wire that connects from the top, from the battery I believe. Another thing I noticed is that the wire I speak of connects through a terminal that you fasten using a nut. This terminal has a "wing" structure bent down towards the at a 90 degree angle. That wing structure has been bent so it doesn't make contact with the alternator. If you understand my wacked descriptions, can that cause a problem? Is that some kind of grounding point?

Typical alternator wiring has one heavy cable going to the battery. Then there is a plug for the rest of the connections. The heavy cable carries the charging current (10's of amps) while the plug carries current for the field windings and possibly voltage sensing.

Check the voltage at the battery positive terminal and the alternator connector. They should be the same under all conditions. If not, you've got a bad connection.

What you've described is NOT a ground. But if it's connected to ground, the alternator will put out full current. It may be enough to heat the terminal. The alternator will probably survive this since the current is supposed to be limited by the regulator to what the alternator can safely produce.

Thanks Kurt,

Last weekend I disconnect the cable going to the battery and cleaned off some grime and rust that had settled there as well as on the top of the alternator where it connects to. The problem hasn't returned and I've put on a full load, put on dir and hazzard lights, high beam, radio...the works.