Q: Battery light coming on faintly after installing new alternator

asked by on

Changed my alternator yesterday, the battery light keeps coming on lightly. It gets brighter as I accelerate. Headlights dont dim when I rev the engine though.

My car has 237000 miles.
My car has an automatic transmission.

Hi there. Have you had the battery tested? Use a digital battery tester that provides current voltage, cold cranking amps, and state of health. Any corrosion on the terminals? This could present an opportunity for electrical disturbances and create concerns. However, this does sound like the alternator or belt is at fault. Check for proper belt tension and belt condition to ensure that it is not slipping. If it is slipping, then adjust/replace as necessary. If this checks ok, then the alternator may be at fault. Even new parts can be faulty and a proper load test will uncover whether or not it is indeed faulty. When you rev the engine, the alternator spins accordingly and can provide additional voltage/amperage which is probably why the light starts out dim and gets brighter when you do this. I suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several available technicians that can assist you with a charging system inspection.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Battery light coming on faintly after installing new alternator

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

Get a quote

What others are asking

Q: My car won't start - Hyundai Elantra

The first step that should be done is to have a certified technician, such as one from YourMechanic, download any error codes for you and diagnose your illuminated Check Engine Light. If you have a professional digital scanner, you can...

Q: Car wouldn't go over 50 mph I went over and next thing you know I hear loud knocking from the engine

The knocking is suggestive of a mechanical failure of some sort. I would first measure cylinder compression to get a basic idea of the condition of the engine. If it doesn't test well (too low and/or too much variance) you...

Q: Noise when I turn the wheel and go over a bump.

Hi there. It sounds like there could be a fault with the strut mount, strut assembly, outer tie rod, ball joint, or control arm. Recheck for proper torquing of the control arm that you installed and inspect for any other...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.