How to diagnose an alternator or electrical problem?
Diagnosing alternator problems can be a bit tricky because the electrical system in a car comes from two places, the battery and the alternator. I’ll give you a little background so you can understand what both systems do. The battery has one primary function, which is to start the car.
What happens if you have a bad alternator in your car?
The car won’t start at all. If the problem is a bad alternator, your car will slowly lose power. You’ll be driving down the road, your lights will dim, and you’ll lose power and die. If the problem is with your battery, then you’ll generally only have trouble starting your car since that’s the battery’s main function.
What causes an alternator to go over base voltage?
If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty. Other potential problems are a faulty voltage regulator or a problem in the charging system wiring.
Can a car battery be drained by an alternator?
While you might initially think that any problems with electrical things like lights or radio not working are directly related to the battery, the alternator is actually where most of the power in your vehicle comes from. Consider that if you were to leave the lights of your car on overnight by the next day your battery might be drained completely.
What are some common causes of alternator problems?
Common Causes of Alternator Failure Dead Alternator. This one’s pretty obvious. Computer Problem. Newer vehicles are built with computer systems in them such as the ECU. Wiring Problems. There are lots of wires in the vehicle which deliver power to the alternator. Bad Fuse. Vehicles use fuses to keep the alternator functional. Broken Pulley or Broken Belt.
What are the signs of an alternator going bad?
One of the most common symptoms of a failing alternator is flickering, pulsating, or dimmed headlights. If your alternator is beginning to fail it won’t be able to power your headlights effectively.
What happens when the alternator is bad?
If your alternator is going bad, the vehicle will shut down after 20 to 30 minutes. The alternator, as it fails, will drain the battery, causing all electrical systems to power down.
How do I know if my battery or alternator is bad?
Signs of a bad alternator. If the above steps reveal that the battery is working, it’s time to take a closer look at the alternator. There are certain signs of a bad alternator to look for: While running the car, note the brightness of the interior lights. If the dashboard gradually dims, the alternator is likely at fault.
What should the charge voltage be on an alternator?
Turn on the high beams for 10 seconds and then turn them off. Measure battery voltage across the battery posts with your DMM. You should get between 12.4 and 12.6V. This means your battery is fully charged. If you get a reading below 12.4V, charge the battery before continuing. 5b. Measure the Charging System’s No-Load Voltage
What to do if your alternator makes a squealing sound?
If there is a problem with the bearings you may hear a squealing sound coming from the front of the car, which becomes louder with more electrical accessories using power at the same time. Turn the radio on and rev the engine. Tune your radio to a low number on the AM band with no music.
Can a low battery cause an alternator to go bad?
This means that if your battery is too low, you will be unable to start the vehicle and thus you will also be unable to test the alternator, rendering any additional voltmeter-testing totally useless. If the weather is cold or your battery is old, your battery could be the issue and your alternator might be just fine.
Why is the voltage reading on my alternator going up?
While watching the voltmeter display, start wiggling wires at the back of the alternator, the battery, and the remote voltage regulator (if there is one). If the voltage reading on the meter display goes up while wiggling one of the wires, you’ve found a bad electrical wire or connection.
What to do if your alternator is over charging the battery?
Ask an assistant to start the engine and hold engine speed at about 1500 RPM. Measure voltage across the battery with your DMM. You should get 0.5 to 2 volts higher than base voltage. If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty.
Why does my voltage guage only show 9-10 volts?
My voltage guage usually points near the red mark at 9-10 volts. Batteries cranks the starter quickly and it does not seem to lack any electric power. Some times driving, it will raise to about 12 V, but never above, and the next minut point at 9 again.
What should the dash gauge be right after start?
Right after start, at the alt or batteries (doesn’t mater) it will be low – the batteries are charging. Wait 5 min then measure. It should be 13.8 volts. If its 12 its too low. Alt neefs replaced. The dash gauge in these trucks is a joke. Huh, my answer when reading the post title was gonna be,,,, Stock gauges suck!
How often does an alternator need to be replaced?
How long does the alternator last? On average, an alternator fails after 100,000-150,000 miles. In cars that are driven daily, an alternator tends to last longer. Tip: one of the reasons an alternator can fail prematurely is when an engine splash shield is broken or missing and road dirt and moisture can get into the alternator.
What happens when the diodes in an alternator go bad?
Alternators use diodes to rectify alternating current produced by the alternator into direct current. When one or more diodes go bad, the alternator can cause all kinds of problems. AC voltage leak can cause your lights to dim and drain power from your battery, for example.
How can you tell if your alternator has died?
To do a quick check on an alternator, I was told that you could start the car and then remove the negative battery cable. Doing this would allow you to check whether the alternator is putting out enough current to run the vehicle. If the engine cuts off, it is a sure sign that the alternator has died.
What’s the best way to safely test an alternator?
Best way to safely test an alternator. Best way to safely test an alternator. To do a quick check on an alternator, I was told that you could start the car and then remove the negative battery cable. Doing this would allow you to check whether the alternator is putting out enough current to run the vehicle.
How long does an alternator last in a car?
When your engine is running in your car, the alternator is in charge of giving the battery power. The alternator is typically a maintenance-free generator of electric power. However, with poor care, you might have to replace or rebuild the alternator sooner than you think, despite the alternator typically lasting 10-15 years in most vehicles.
Why does my alternator not work when I start the car?
When you start the car using the battery, the alternator provides its power to keep the light on constantly. If the light glows properly, the alternator is working fine. But if the headlight is dim or keeps flickering, your alternator is struggling to power up the battery. The performance of the battery also is a crucial sign of a bad alternator.
Why does the battery light come on after the alternator is replaced?
This would make the Battery Light come on. It is also possible that there is a problem with the fusible link or the alternator fuse for the charging system.
Diagnosing alternator problems can be a bit tricky because the electrical system in a car comes from two places, the battery and the alternator. I’ll give you a little background so you can understand what both systems do. The battery has one primary function, which is to start the car.
What does it mean when your alternator stops charging the battery?
Indicator Light On. Usually, the first sign that your charging system is in trouble is a “battery,” “ALT,” or “CHARGE” warning light illuminating on your instrument panel while driving. It means that for some reason, the alternator has stopped charging the battery and your car is running on battery power.
Can a Saab 92 start with a bad alternator?
Dual ignition coils (the blue cylinders at the top of the picture) on a Saab 92. Before you go out and order a new battery or alternator, test some of these different systems. If your alternator, coil, battery, or starter is bad, the car probably won’t start, and it definitely won’t be drivable.
Why does my alternator get higher than base voltage?
You should get 0.5 to 2 volts higher than base voltage. If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty. Other potential problems are a faulty voltage regulator or a problem in the charging system wiring.
What are the warning signs of a failing alternator?
The Warning Signs of a Failing Alternator. Indicator Lights. Most modern cars have a dashboard warning light to alert you to a problem with your alternator. Typically this light is shaped like a battery, although some warning lights may display GEN (for generator) or ALT (for alternator).
If you are getting more than 2 volts above base voltage, most likely your alternator is over-charging the battery or the battery is faulty. Other potential problems are a faulty voltage regulator or a problem in the charging system wiring.
Do you need a multimeter to check an alternator?
This is done with a multimeter. You don’t have to use a multimeter if you have alternator problems of a mechanical kind (pulleys, bearings or else). These kind of problems will manifest themselves in other obvious ways (grinding or screeching noise, snapping of the serpentine belt or else).
What causes an alternator pulley not to work?
Not replacing it on time, stuck alternator pulley or a faulty bearing are common causes of this problem. Worst thing about this problems is that it can snap at a moments notice. Main causes of alternator problems (at least from what I’ve seen) are: This is the first and most common reason of them all.
Is the battery good with a new alternator?
Battery voltage was too low to test, so I took battery out and left it out overnight, next morning picked it up, they said battery was good and held charge. Put battery back in and took it for testing, their test said the voltage regulator was bad, so bought a new alternator, installed it, same thing, not charging.
Is it time to replace your alternator wrench wench?
Wrench Wench has been in love with automotive mechanics for decades. She loves sharing advice with fellow DIY mechs and curious cats. Alternators are really not complex mechanical components. They are a type of generator that creates an alternating current.
How much does it cost to replace an alternator?
Alternator Prices and Installation. Make sure that your current alternator is beyond repair first before getting a new one. Alternator prices can vary greatly by make and model, but generally speaking, new alternators should run around $250 without labor for installation.
Battery voltage was too low to test, so I took battery out and left it out overnight, next morning picked it up, they said battery was good and held charge. Put battery back in and took it for testing, their test said the voltage regulator was bad, so bought a new alternator, installed it, same thing, not charging.
Alternator Prices and Installation. Make sure that your current alternator is beyond repair first before getting a new one. Alternator prices can vary greatly by make and model, but generally speaking, new alternators should run around $250 without labor for installation.
How can I tell if my battery is a manufacturing fault?
Examination of the battery will typically show low acid level and usually a black coating on filler plugs and a strong smell. It is recommended that the alternator charging voltage is checked by a mechanic. This is not a manufacturing fault.
When do you know if your battery has a short circuit?
Short Circuit/dead cell Typically seen in a battery within 12 months service life. One cell will show a dramatically lower acid specific gravity reading than the others. The problem cell will usually boil visibly under a high discharge, all other remaining cells will show a good specific gravity reading of 1.26 or above.
How does battery design affect digital conductance test?
Different battery manufacturing design techniques can significantly effect the reading on one digital conductance tester as common algorithms have to be used. For example, batteries designed with more durability in mind tend to carry more material and higher density, this is usually reflected in a lower initial voltage, but longer discharge times.
What does the charge indicator light mean on a car?
Indicator Light On Usually, the first sign that your charging system is in trouble is a “battery,” “ALT,” or “CHARGE” warning light illuminating on your instrument panel while driving. It means that the alternator voltage output is below 12 volts, or over its limit or has stopped charging the battery and your car is running on battery power.
What is the problem code for Pontiac check engine light?
P1113Intake Resonance Switchover Valve Circuit P1114Engine Coolant Temperature (ECT) Sensor Circuit Intermittent Low Voltage – Read Our Article on Automotive Circuit TestingFor Help With This Pontiac Trouble Code
What is Pontiac check engine light code p1115?
P1114Engine Coolant Temperature (ECT) Sensor Circuit Intermittent Low Voltage – Read Our Article on Automotive Circuit TestingFor Help With This Pontiac Trouble Code P1115Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage – Read Our Article on Automotive Circuit TestingFor Help With This Pontiac Check Engine Light Code
How can you tell if your car charger is in trouble?
Usually, the first sign that your charging system is in trouble is a “battery,” “ALT,” or “CHARGE” warning light illuminating on your instrument panel while driving. It means that for some reason, the alternator has stopped charging the battery and your car is running on battery power.
What causes an alternator to stop working on a car?
Once the alternator stops working, so do all of the electrical systems required to keep a car going. Other problems can also cause a car to not start. It could be a bad starter, corroded cables, or a broken connection somewhere between the battery and starter.
How long does it take to install an alternator?
If you need to have it installed by the mechanic, then the price might be a bit higher. Depending on where your alternator is located within the compartment, the installation might only take an hour. But if the alternator is difficult to access, it might require removal of other parts and it could take many hours.
What to do if your alternator fuse is blown?
Check the fuses in the underhood fuse box. There are also some fuses there that are bigger and square with a clear prastic top. Check those with a flashlight. Shine it inside it and see if the fuse is blown. No worries, I’ve been out all day until now. So I think we got something. The 100a fuse for the alternator was melted]
Where can I buy an alternator and battery tester?
AutoZone carries a wide selection of alternator and battery testers and features the lowest prices on alternator testers. Purchase a portable tester for your car’s emergency kit or keep a premium option in your garage as part of your routine maintenance.
The car won’t start at all. If the problem is a bad alternator, your car will slowly lose power. You’ll be driving down the road, your lights will dim, and you’ll lose power and die. If the problem is with your battery, then you’ll generally only have trouble starting your car since that’s the battery’s main function.
Why does the voltage gauge move up on an alternator?
If the voltage gauge is slightly higher than it used to be, and that could happen if the voltage regulator is built into the alternator, and the temp is only slightly higher, that is simply that the temp gauge is measuring a percentage of max voltage. If the voltage is higher, then the gauge needle moves up.