1999 Olds Aurora 88,000 mi.
I began to have intermittent display of "Service Vehicle Soon" on the DIC. When this display occurs the cruse control and air conditioner goes off. After a short time the displayed message went off and all started working again. When I had AutoZone check codes - they said that it was slow idle. An outo shop said that the code was high alternator output and wants $1,000 to replace alternator. They replaced the Battery. I have been monitoring the voltage display on the DIC - usually displays 14.4 - 14.7 v. but on a recent 1,000 mi. trip the voltage spiked to 17. v. and cruse and Air conditioner went off for about 40 mi. then everything returned to normal for the remainder of the trip.
From some old threads it seems unclear that replacing the Alternator resolves the problem. Does anyone have better information on this subject?

17 volts is way to high and the only thing that would do that is the alternator. Try replaceing it your self or get a few estimates.

Welcome to AF Tex!

Did the Zone say exactly what the code was ?
Slow idle could be several things, but should not be causing the spike in voltage.

Might not even be the alternator, could be a loose/broken wire shorting , even a bad relay for the cruise/AC could cause a high voltage.

Could easily have the alternator load tested to see if that is whats wrong before you replace it.

good luck

These cars have a temperture controlled voltage regulator located close to the battery under the back seat. It allows the voltage to increase if its extra cold out or something. This is most likely your problem, not the alternator. There are other threads on this topic. I believe it is called the battery thermistor.

Here are a few threads on the topic of battery thermistor.

http://www.automotiveforums.com/vbulletin/showthread.php?t=503355&highlight=battery+thermistor

http://www.automotiveforums.com/vbulletin/showthread.php?t=667303&highlight=battery+thermistor

http://www.automotiveforums.com/vbulletin/showthread.php?t=519267&highlight=battery+thermistor

Hope that helps!

Hello There;:iceslolan

This is one of those funny things about the Aurora. I got told it was the voltage regular. Replaced it no problems. To replace your alternator is
about $ 500.00.:licka: :licka:

There is a place in Los Angeles, that sells and rebuilts them For about $ 200.00 including shipping. Takes 2 hours to install.:popcorn:

Take care

Driving Along in my Merry Oldsmobile.

Al Galaviz

It's too bad that I didn't get back to my posting sooner. Drove over 1,000 miles with no more overcharging THEN it started overcharging - took the car to a business that specializes in alternators. They checked the alternator said it was bad and replaced it - overcharging continued so they replaced it again at no charge - still overcharged. Then they found the Battery Thermistor or Battery temperature sensor on the battery end of the positive cable. We unplugged it and charging has remained at 13 -14 v. but the "check charging system" displays on the DIC and the battery light is on. I have a Battery Thermistor on order - $50. Thanks for the help - The alternator shop swears that the alternator was fried - but I wonder.

aurora is NOT a regular vehicle. way too advanced for 'regular' shops