2004 Buick Rendezvous battery light goes on

Tiny
EDDIE91335
  • MEMBER
  • 2004 BUICK RENDEZVOUS
  • 3.4L
  • V6
  • 2WD
  • 167,000 MILES
Battery light goes on rev engine and goes away. But still no charge. Volts are 11.7 at the alternator or battery terminal
also how hard is to replace it, they mechanics ask my wife for over 450 parts and labor, please help
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Thursday, March 12th, 2015 AT 7:34 PM

3 Replies

Tiny
CARADIODOC
  • EXPERT
I can't speak to the difficulty, but starting in '87 with this design, GM generators have an extremely high failure rate. They develop huge voltage spikes that can destroy the internal diodes, voltage regulator, and interfere with computer sensor signals. To reduce the number of repeat failures, replace the battery at the same time unless it is less than about two years old. As they age and the lead flakes off the plates, they lose their ability to dampen and absorb those spikes.

You're right about the charging voltage. When it's working properly, you'll find between 13.75 and 14.75 volts with the engine running.
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Friday, March 13th, 2015 AT 3:19 AM
Tiny
EDDIE91335
  • MEMBER
Thanks you for the respond. But my second question was the most important of the two. How hard is to replace the alternator. Can I do it or I need to take it to mechanic one again thanks ed
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Friday, March 13th, 2015 AT 8:19 AM
Tiny
CARADIODOC
  • EXPERT
GM never designed a vehicle with an eye toward service. Their concern is how it can go together the fastest on the assembly line. Also, there is no rhyme or reason as to where they mount things. The generator can be in one location in one vehicle, and a totally different location on the same size engine in a different vehicle.

I looked up the instructions for yours and found there's a lot of variables that I and probably you can't answer. You're going to have to look for yourself to see if you want to attempt this job. For the choices I selected, there are 16 steps in the list of instructions that include removing engine mounts to roll the engine forward to access some bolts, remove the drive belt tensioner, remove the generator's bracket, remove the power steering pump with a warning to not disconnect the hoses, and other steps.

There's also a tip posted that suggests lowering the engine cradle with the engine on it to make generator removal easier. If you want to try that, don't start until I explain what can happen to handling and steering response, and how to avoid those miserable problems.

I wasn't able to copy and paste the instructions. Your best bet is to get a copy of the manufacturer's service manual, then read through the steps with the line drawings to see if you want to attempt this job.
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Friday, March 13th, 2015 AT 5:20 PM

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