Skip the auto shop - Our mechanics make house calls

Q: Do I have a problem with the electrical system?

asked by on

The truck started flashing the battery light and eventually it died on me. I installed a brand new alternator and battery and the next morning the light comes back on and the voltage is very low.

My car has 151000 miles.
My car has an automatic transmission.

Hi, thanks for writing in. The charging system is not very complicated. If the alternator and the battery are absolutely 100% good, no doubts about it, then the issue is likely a bad ground. Both the battery and the alternator are grounded to the vehicle. Without a proper ground connection, the circuit is incomplete. To locate the battery ground, find the negative terminal and trace the grounding strap to the body of the vehicle. Make sure this connection is clean, dry, tight, and protected against the weather. Secondly, check the alternator and its ground. Some alternators ground to its case, while some run a ground strap to a part of the body, frame, or a bolt. You will want to trace the negative terminal on the alternator. This too need to be clean, dry, tight, and protected against the elements. If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect your electrical system for you, and make or suggest any repairs as needed.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Do I have a problem with the electrical system?

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: Engine making chirping sound

Belts chirping or squeaking in annoying but usually not too serious. I've seen brand new belts chirp because of the ink that's on the belt for the part number and barcode. However, it could also be a bearing in a...

Q: Over bumps, chime sounds and warning lights come on

There have been 2 recalls for a failed driver door window power switch which also disables the driver door locking mechanism. These recalls are 14309 (current recall) and 13V-248 (the original recall). Contact your dealer for service under these recalls....

Q: The car shorted out after a repair

It is possible that the powertrain control module may have been damaged during the oil change at the time of the short. I would have the powertrain control module tested with a high tech scan tool if this option is...

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...