What battery cable do I remove to test alternator?

Do you take the positive or negative off to test the alternator?

If you're tempted to test an alternator by disconnecting the negative battery cable, don't do it. A good alternator may indeed keep the engine running without the negative cable, but this was never a good test. In the pre-computer days, you could pull it off without damaging anything.

What battery cable do I remove to check alternator?

You can check the alternator by simply starting your car and then disconnecting the negative battery cable. Be careful doing this, though, because there are a lot of moving parts in your engine compartment that could cause injury.

How do I test my battery and alternator?

A simple test to check the working of the alternator is by running your car; and then unplugging the positive connection of the battery. If the car stops, then you most likely have a problem with the alternator.

How do you test your alternator?

Battery or dead alternator test?

How does AutoZone test your alternator?

We can do a charging test in the parking lot which tests the battery, and will determine whether or not your system is charging properly. This test may not pinpoint whether the alternator is bad or not, but you can also remove the alternator from your vehicle and have it tested at the nearest AutoZone auto parts store.

Which fuse is for alternator?

But when someone mentions the “alternator fuse”, they're generally referring to the primary, high-amperage fuse (or fusible link) between the alternator and the battery. Like any fuse, the primary alternator fuse acts as a circuit protection device.

How can I test if my alternator is bad at home?

A battery test is easy to perform and can be done at home. First, open the hood and start the car. While the engine is running, remove the negative cable from the battery. If the vehicle stalls or dies, the alternator is likely bad.

What happens when you disconnect the negative battery cable while running?

If your alternator is malfunctioning by over-charging your battery, disconnecting it may allow the alternator to provide an even higher voltage to the car electronics, and potentially damage those sensitive components.

Can you hook jumper cables to the alternator?

While jumpstarting a vehicle with a bad alternator may technically be possible, do not leave jumper cables connected between vehicles longer than necessary as it can result in damage to sensitive electronics. See here for more info.

What is draining my car battery when its off?

What may drain a car battery when it's off are things such as interior lights, door lights, or even bad relays. While your engine runs, the alternator recharges the battery — which is why you typically don't have to worry about the battery dying while you're blasting the radio on your drive to work!

Can Oreillys check your alternator?

Your local O'Reilly will test your alternator for free on or off your vehicle so you can know for sure whether or not that's the problem with your vehicle.

Which alternator terminal can be grounded for test purposes?

The rotor field coil is connected to terminal "P, which is accessible for testing purposes through a hole in the alternator end frame. While engine speeds and electrical loads change, the alternator's output must remain even - not too much, nor too little.

Why don't you connect the negative when jumping a car?

Quick Tips: Jumping a Battery

Never connect the black cable to the negative (–) terminal on your dead battery. This is very dangerous, as it could result in an explosion.

Will an alternator recharge a dead battery?

But when your car is running, your alternator is fueling the battery for the next start. In order to fix a dead battery that is still carrying a good amount of voltage, driving around might be all you need to do. As we said before, the alternator will recharge the battery while your car is in motion.

Is it OK to just disconnect the negative terminal?

Disconnect battery negative cable

It is a good practice to always disconnect your negative battery terminal first, to minimize the risk of sparks that can lead to car electronics damage and battery explosion. Once you have located the negative terminal, use the wrench to free the nut that tightens the terminal.

Will removing the negative battery cable reset computer?

While disconnecting the battery will not permanently damage your vehicle's computer, it can cause it to function differently. That's because, if you disconnect your battery for long enough to reset the computer, it may cause the processor to forget everything it has learned.

Is it OK to just disconnect the positive terminal?

Be safe: always disconnect negative first. Disconnected either terminal will prevent drain, as stated already. A battery tender is another safe way to maintain the battery.