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George H.
George H., ASE Certified Technician
Category: Saturn
Satisfied Customers: 810
Experience:  ASE Master Tech 15+ Years
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Daughters Saturn vue had an alternator go....had it

Customer Question

Daughters Saturn vue had an alternator go....had it replaced...first 35 degree morning started it inside lights...outside lights go crazy....shut it off,restarted everythings good..next morning same thing.....had a reman. ac delco put in....started this morning pushing 20.7 volts on the meter...shut it off...unplugged the alternator restart reading 13.....plugged back in....reads 14....all is good seems to only happen on the cold days
JA: Just to clarify, what are the exact lights you're talking about?
Customer: headlights...dome lights.....dash lights.....this morning when it was charging at 20.7....lights, radio lights, dash lights didn't even come on
JA: What is the make/model/year of your car?
Customer: 2006 Saturn Vue ...front wheel drive...3.5 liter
JA: Are you fixing your VUE yourself? What have you tried so far?
Customer: So far just the alternator replacements....put and after market...did it was told to use an ac delco...OEM still did it....someone said voltage regulator....but 2 in a row....
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 3 months ago.
Category: Saturn
Expert:  Ronnie replied 3 months ago.

Hello. My name is ***** ***** I am happy to assist you today. Give me just a moment to review your post, and I'll be right back with the help you need.

Expert:  Ronnie replied 3 months ago.

Your charge rate is controlled by the duty cycle from the PCM (computer) and in most case this type of a overcharge will cause the computer to set and store a fault code. Have you scanned the system to see what the fault code and or codes are?

Customer: replied 3 months ago.
nothing has come up on a code in the car....runs great in the warmth....at 35 degrees goes crazy....was at 12.3 volts before starting this morning then hit the 20.7 volt charging rate. shut it off....restarted...was @13 v....plugged alternator back in went to 14 and was fine
Expert:  Ronnie replied 3 months ago.

Its over charging at 20 volts and this can cause all sorts of issues as well. Have you connected a scan tool to the system to see if the PCM is setting any codes. All your doing when you shut it off is resetting the computer. The problem may very well be with your computer. A code scan needs to be done.

Customer: replied 3 months ago.
will it still read a code when its running the way it should....don't want to sound dumb just need to know if I have to hook my scanner to it first thing in the morning when it does it or if it is prevalent
Expert:  Ronnie replied 3 months ago.

In most case the computer should set and store a fault code and hold it. It dose not have to be running, turn the key on and scan it and lets see if there are any codes in memory.