How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask GM Bob Your Own Question
GM Bob
GM Bob, ASE Master Technician
Category: GMC
Satisfied Customers: 1134
Experience:  30 plus years experience as GM technician, ASE Master Technician and GM Certified
Type Your GMC Question Here...
GM Bob is online now
A new question is answered every 9 seconds

While driving the charging gauge will drop from 14.2 to 12 v

Customer Question

While driving the charging gauge will drop from 14.2 to 12 v and jump back and forth .iv been told that's ok but I know that's not true it didn't happen for the first 8 months what should I do
JA: What is the model of your '14 GMC?
Customer: 2015 sierra
JA: Are you fixing your Sierra yourself? What have you tried so far?
Customer: No its gone to dealers
JA: Anything else you want the mechanic to know before I connect you?
Customer: I've had other electrical problems but I'll deal with those later
Submitted: 11 months ago.
Category: GMC
Expert:  GM Bob replied 11 months ago.

Hello my name is Bob

The system as several modes. This is a common complaint on GM trucks.

Sorry to let you know it is normal.

Here is a link on how the charging system works.

Half why down the page is Charge Mod / Fuel Economy Mode.

Hopeful this will help.

Please let me know if you have more questions

Expert:  GM Bob replied 10 months ago.

Was this helpful?

Do you need more help?

Expert:  GM Bob replied 10 months ago.

If you can take a moment and rate my service.

Thank you