Q: lights dim , radio shuts,down all rear lights come on in flashing mode when accelerating.

asked by on

Alternator putting out 16.5 volts when accelerated. Is the alternator regulated by: internal alternator regulator, PCM Unit or Body Control Module?

My car has 57000 miles.
My car has an automatic transmission.

Hello, thank you for writing in. On your vehicle, there will be a "voltage regulator" located on the inside of the alternator. It will be controlled by the PCM. When dealing with the charging system it is important to have the battery tested as well. While it can be the cause of many strange electrical symptoms, a failing alternator can also put extra strain on the battery causing premature failure. Both of these can be tested at most automotive parts stores. 16.5 volts when accelerating is extreme, but it may be trying to compensate for a battery issue detected by the PCM. For more diagnostic help, contact our service department to schedule an appointment.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 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. lights dim , radio shuts,down all rear lights come on in flashing mode when accelerating.

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: Q: Battery keeps dying out

Hello. Typically when these symptoms occur with the security light on, it is always the ignition switch that is causing this. It can also be a short in the electrical system, but most of the time, it is caused by...

Q: My van won't turn over to start it just clicks

It sounds like you may need a starter. The testing for it is pretty straightforward. Check the battery cable going to it, and check for power at the start wire. If there is power at both, it will need a...

Q: Q: No air coming out of vents

The major components of the blower fan system include the switch on the dash, the blower motor resistor, the fan itself, and wiring in between. Any of the above items could be the cause. A diagnostic procedure will determine your...

Related articles

How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.