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: Tachometer slowly rises while driving (1500 rpm after 5 min, 4000 rpm after 10) regardless of gear

Hi there. Check the VSS (vehicle speed sensor) on the transmission for any loose wires. If the wires are tight, then remove the VSS and clean it off, then put it back in and retest. If the symptoms come back,...

Q: Stalling after cold starts and problem with lights

It sounds like you have a sticking idle air control valve that frees up after the component warms up. The valve may be able to cleaned if there is a great deal of carbon build-up inside the valve. As...

Q: Car won't start, needs alternator.

Hi there, I am not sure why all those components were replaced, but we can at least rule them out. A car basically uses the battery during start up. It provides power to the starter. Once the car is running...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...