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.

A: Hi, thanks for writing in. The charging sys...

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!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Serpentine belt came off of 1995 Chevrolet Camaro

If the belt was replaced prior to purchasing it, and the belt immediately broke, there could be another problem. Most likely one of the pulleys used as an idler or for one of the accessories could be seized causing the...

Q: Stereo shuts down when steering wheel is powered on

These are probably two unrelated issues. In regard to your vehicle, the body control module (BCM) receives input from the door lock switches. Then, based on the received inputs, it either locks or unlocks the doors via the door lock...

Q: battery not charging light came on

I would still recommend getting the alternator and battery tested. The most likely cause would be the alternator. The alternator can have an intermittent failure that causes it to charge and not charge randomly. If this turns out to be...

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...
How to Renew Your Car Registration in Oklahoma(DELETED)
Having your car registered with the Oklahoma Tax Commission is an important part of driving legally in this state. You will need to do this within 30 days of moving to Oklahoma...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...