- Nov 20, 2017
- Reaction score
- NW GA
Friend had a Arcadia with lots of scary wtf voltage issues in his trip from CT to NC. Dealer checked it no issues. Blah blah eventually they did replace the alternator!Perfect timing for this issue and my current circumstance. Hope you don't mind me jumping in here but it sounds like there is a fairly good knowledge base and I don't trust what the dealer told me.
I have a 2018 GMC Sierra Denali. I have owned it from late 2019. The voltage gauge always read somewhere just below or just above 14v.
About a month and a half ago it started to drop to as low as 12.3-12.5v. Sometimes stay there sometimes jump back up on its own. I had the battery tested and it had lost a step in holding charge. I expect that for a OEM battery that is 50-48 months old. Replaced the battery. Same thing happened.
Pulled the alternator took it to three parts stores to get it tested. They all said the same thing that they did not have the connector to test it with on their machine. I found that weird since the its 4 years old. I guess they don't update those machines much.
Read a bunch of Chevy forums with many claiming the computer in the truck tells the alternator how much voltage to put out based on load. OK I accept that to a point but I am still skeptical. I can be rolling down the highway, lights, cooled seats, A/C, wipers etc all on and the voltage can go from 14v to 12.3v-12.8v and stay there. (I have a phone charger with a meter on it and I had a ProM both read very close to the dash gauge reading and all read the same).
If I pull over after running that way for a while turn off the truck then turn it back on it jumps to 14.5 to as much at 15v at times. That tells me the computer senses that the battery has been starved and it needs to charge it.
The dealer said all is good, no codes no issues found. The truck is under the bumper to bumper so if they found an issue they would have replaced the alternator or what ever they found defective. They did not replace it. At least they did not charge me for the diagnosis. Its still happening this week.
I don't want to get stuck on a winter night when I go out to the car and find it dead.
I am thinking just go ahead and replace the alternator and see what happens. What do you all think?