Alternator?
Alternator?
lets start by saying I have some knowledge when it comes to mechanics, but at this moment I am at a loss, last night I was driving home from work about 10mi and my volt gage was reading about 8 volts, way too low. but I was running my stereo, headlights, and the vehicle without the gage dropping any, I made it home and let the car sit over night, started with no hiccups other than the gage reading low, drove to my bank and the TC light & ABS light came on and said service stability system, i drove to the local orileys and had the charging and starting sys checked, the battery read needing a charge but ok with vehicle off, then started the car no problem again and the machine said the starter failed, the alternator and the voltage regulator were giving bad readings, I have been looking to see if I could find easy ways to replace my alternator if that is even my problem, any help would be greatly appreciated
- JaxGXP
- SE Member

- Posts: 14
- Joined: Fri May 13, 2011 5:39 pm
- Year and Trim: 2005 Bonneville GXP
- Location: Jacksonville, Florida
Re: Alternator?
My 2005 GXP experienced these same symptoms a few weeks ago with the additional indication on the DIC of "entering battery saver mode". It was diagnosed at a GM dealer as a bad alternator. The dealer recommended a Delco alternator, which they did not have in stock, at an ungodly price. The local NAPA had a rebuilt unit (145 amp) with a three year warranty in stock for $149 plus core charge. I provided the NAPA alternator and had the dealer install it since the vehicle was already there. I'm not sure I would want to attempt an alternator change without the use of a lift since it is not very accessible from the top. Good luck if you decide to do it yourself.
- CMNTMXR57
- Certified Bonneville Nut

- Posts: 5841
- Joined: Wed May 13, 2009 10:45 pm
- Year and Trim: 2006 STS-V, 2004 GTO, 2009 G8 GT
- Location: CHICAGO
Re: Alternator?
Actually, it really isn't too difficult to replace the alternator. You may or may not have to remove the cooling fans to allow room. But otherwise, it's removal of belt, disconnect 2 or 3 electrical connectors attached to the harness, then 3 bolts.
To me, it sounds like the voltage regulator. But another thought I have is that it could be "power moding" or more or less the electrical systems' way of regulating electrical load. Do you notice it trying to raise the RPM? Do you notice it trying to reduce electrical load (I.E. shutting off A/C, heated seats, rear defreoster, or blower motor)? If it is, this is another issue.
To me, it sounds like the voltage regulator. But another thought I have is that it could be "power moding" or more or less the electrical systems' way of regulating electrical load. Do you notice it trying to raise the RPM? Do you notice it trying to reduce electrical load (I.E. shutting off A/C, heated seats, rear defreoster, or blower motor)? If it is, this is another issue.

Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*
Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ
Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2011 Camaro SS
2009 Pontiac G8 GT: L76, Sport Red Metallic
2004 GMC Sierra 2500HD: Victory Red - 8.1L Big Block and Allison
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... RIP
1999 Chevrolet Suburban: Sunset Gold Metallic - RIP

