Field coils and armature
It would be best to remove the alternator and take it to an electrical shop.
The brushes on an alternator carry current.
The brush holder in an alternator keeps the brushes held to slip rings with spring pressure (or commutators in generators or some motors) which provide electrical contact to electromagnets in the spinning rotor. By varying the electrical current through the brushes to the rotor magnets, you can adjust the power output of the alternator as needed.
There may be a drain on the electrical charging system.First place to look would be the alternator.Put a tester on to the alternator to see if it is faulty.Check brushes in alternator.
A bad belt, a bad regulator in the alternator or bad brushes in the alternator.
Change alternator or check alternator brushes
Stator, armature, rectifier, bearings, brushes,
Is it possibly a broken/missing alternator or serpentine belt? (nope just alternator light) It can also be a failing voltage regulator within the alternator, or a failing alternator itself. It is usually the carbon brushes in the alternator when both lights come on, it indicates a field problem with alternator Brushes are not to hard to change on a toyota, just remove the alternator from car, remove rear cover unscrew the brush holder and rectifier?(they are attached together) and install new brushes... you will need a soldering iron. It is a simple repair and at less than 10$ is more affordable than replacing the alternator. VW and Volvo have removable brush holders that unscrew from back of alternator Gm Ford and Mopar, you may have to split alternator to change brushes, there is often a small hole in back of alternator where you can use a piece of wire to keep brushes compressed when you put alternator back together easy job ... save your money
Regulator is mounted on the back of alternator. It is replaceable if you can find parts. Brushes are there also.
A failing alternator with sticky or worn out brushes.
Have you measured the voltage across the battery with the engine running? It should measure approximately 14v. If not you want to replace your alternator/voltage regulator. Check your shop manual to see if you can open the alternator and replace the brushes. After so many miles the brushes wear down, this is the most frequent cause of alternator failure. there is a fusable link in the line between the battery and the alternator i replaced the battery and alt. but still wouldn't charge track the wire
Brushes transfer electricity to the commutator which is connected to the winding on the armature. The brushes and commutator form a electrical connection that is good when the brushes are stationary and the commutator is spinning. The commutator on a DC motor is sectioned to power different windings at different times, creating moving field necessairy to pull the armature off a direct current.