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・Fair and transparent pricing

Get a quote

What others are asking

Q: when it gets a little warm it starts missing and cutting out. It wont start back until it cools off

Hello, and thank you for writing in. When the vehicle develops issues related to the temperature of the engine, the first thing to do is see if it is overheating. To do this, you will need to external tool to...

Q: Car starts & drives well, but quits after one mile

Hello there, thank you for asking about your 1987 Oldsmobile Toronado. There was actually a recall on your vehicle for stalling; it's number 87T816E. Stalling was such a severe issue with this vehicle that GM decides to extend the warranty...

Q: Engine overheating - 1994 Mercury Capri

Hello. I usually start by checking to see if the thermostat is opening as it should and see if the engine cooling fan is functioning. If the fan is not turning on, then that needs to be repaired. If the...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
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...
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...