Q: Changed alternator and battert, light still on and car dieing

asked by on October 22, 2016

Changed alternator and battery and light is still on and battery dieing.... what do I do next...which fuses should I check, where is the fuse link and how do I check it? What else could it be?

My car has 200000 miles.
My car has an automatic transmission.

Car is hard to start Inspection $94.99 - $114.99 Get a Quote

This may suggest a bad grounding issue or potentially a failing voltage regulator. This is a unit that regulates the charging of the battery by the alternator. Often times this will result in the alternator allowing too much power to be delivered to the battery resulting in damaging wires and prematurely sometimes destroying the battery. In other cases it may result in the alternator not supplying enough power to the battery, resulting in undercharging the battery or not charging it at all. In either case, I would recommend having an expert from YourMechanic come to your location to diagnose and properly test your vehicle’s charging system.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

I DROVE THRU A FLOOD & MY CAR STALLED. NOW THAT IT STARTS ITS KNOCKING... WHAT CAN BE CAUSING THIS?
If you drove through deep water, chances are your engine took in some water and did internal damage to it. When engine suck in water, they cannot compress the water that gets into the cylinder, so it usually locks up...
My car wouldn't start one day but started fine the next.
For this vehicle, the wiring harness connections on each and every module may have what is called "fretting corrosion", which will cause intermittent loss of connection in the module. A certified mechanic will have to go through each and every...
Car sputters when i accelerate
This problem may be from a throttle position sensor's erratic computer input. This can cause hesitation on acceleration or a light tip in lag. Buick has issued a technical bulletin: 05-06-04-058 which calls for the replacement of the throttle position...
low idle around 400 rpms
This generation of Lexus GS models has a known issue for this and can often be corrected by cleaning the throttle body (https://www.yourmechanic.com/services/clean-throttle-body). I would also recommend testing the MAF (Mass Air Flow sensor (https://www.yourmechanic.com/services/mass-airflow-sensor-replacement)) as well as this can...
Glow plug
Like the Check Engine Light, the glow plug light on late model diesels can come on to indicate a problem in the engine control system. Even when the light is out, there should be a trouble code stored in the...
EGR valve is closed when I accelerate and it opens when I remove my foot from accelerator. What is wrong with the EGR valve?
Hi there. If you are getting the EGR valve to operate in the opposite times, then check the harness for power and see if the power is on with the engine at idle. Check the voltage and there should be...
Can you change the defected water pump without changing its defected belt (which is the drive belt and only belt in this model of
Hello. Yes you can replace the water pump without replacing the serpentine belt. If the belt is worn, and it breaks while you are driving, you can damage a lot of other components in that area. Typically the price of...
Accelerator doesn't respond
Hi there, Your car's throttle control system is comprised of a few different components that all work together to control the throttle as you press on the gas pedal. The foot pedal position sensor (https://www.yourmechanic.com/services/throttle-position-sensor-replacement) relays the position of your...
2003 altima will not start after replacing CPS, checking spark and replacing fuel pump
Whether the fuel pump is new or old, the pressure has to be tested on the fuel rail to be sure the pump, and other fuel system components such as the filter, regulator, etc., are actually working. If the fuel...

Related articles

How to Charge a Car Battery
In In an age where it seems every moment is tied to a schedule, the last thing you need is to find yourself stranded when your car doesn't crank due to a dead battery. It doesn't matter whether you're at...
How to Replace a Coolant Vacuum Valve Switch
A vacuum line attaches to the vacuum switch in your car as part of the engine’s heating and cooling system. A faulty switch can break your heater.
How to Adjust an Alternator Bracket
Alternator bracket replacement typically means an entire alternator belt replacement in modern cars.