Expert: Rob Painter - 4/26/2010

Question
I have a 1996 Eldorado ETC and a warning of Check Electrical System has come on, the car idles rough and sometimes stalls, the volts are running rather low at 12.3 to 13.4. I have checked the battery cables and the alternator was replaced within the last two years. What else should I check??
Thank you!

Answer
Hello,

You appear to think that because the alternator is only 2 yrs old that it can't be the problem and yet my money is from the voltage regulator in the alternator. If you have a lifetime guaranty on the alternator, take it back.


Hello,


Well as your rating comments came back, of which I did not appreciate, nor was I being rude as you accused me of, I attempted to keep my answer short and to the point. #1, I obviously am not physically at your vehicle. I have no idea as to who and how the alternator was checked. I have seen countless times that parts people at places like Pep Boys, Auto Zone and the like have no clue as to how to check alternators, starters and batteries and they should not be out there diagnosing electrical problems. This is not their expertise. This is the purpose of a good mechanic diagnosing the problem. Do I know this is your situation no!

My purpose on this site is not to get into arguments. I don't need it. I do not get compensated for my time to answer these questions. I volunteer my knowledge in an effort to help people. I have had many people over the years praising my answers for accuracy.

Now, I have no idea of who is looking at the car for you. I have no idea, as to what his or hers qualifications are when it relates to these issues. I will tell you I have well over 30 years working on this junk. I have 11 years with GM dealers and another 19 on my own. ASE certified, the whole bit.

As a general rule if you are not getting sufficient voltage and are not up to the 14.2 required, there are only 2 possible answers (remember I am not at your vehicle to see if someone has done some sort of rigging to the factory wiring), one is a very remote chance where the battery will not take the charge of the alternator and the only other thing left is a defective voltage regulator in the alternator. I notice you gave me voltage, but you did not give me amp output although voltage is enough.

What options do you want? Should I start making things up to cost you more time and money?

I do not appreciate your response whatsoever and I am getting real tired of that select few people that want to argue with me.

If you have that much confidence in whoever is diagnosing your car, why bother writing me?

After some thought on this, my suggestion is take the car to a real mechanic and pay the price for getting the alternator repaired or replaced.

I am not going to make options that will not help you. In your situation, the answer is cut and dry. Insufficient voltage out put, the alternator because it is the only real option you are left with.

Am I supposed to say--replace all wiring harnesseses under the hood.

It's obvious you had your mind made up about the problems long before you wrote me.

Now, I will no longer be addressing people's electrical problems thanks to your rating.

If we keep this up, I won't be answering any questions shortly.