Saturn SL 1 Battery Problem

JEFFYONKER

MEMBER
1996 SATURN SL1
4 CYL
FWD
AUTOMATIC
120,000 MILES

My daughter has a 1996 Saturn SL1. While she is driving, the "check battery" light on the dashboard goes on and the headlights dim. She lives in Michigan and the battery is 5 years old so is it time to replace the battery or is there a problem with the alternator? I'm looking for the cheapest option becasuse we only need to get 6 more months out of it until she finishes college.

1 Reply

CARADIODOC

MECHANIC
33,755 POSTS

It means the battery is not being recharged by the generator, but there's more to the story. Due to GM's really terrible design, the generator was most likely destroyed by the battery. It is common to go through four to six of these generators in the life of the vehicle. To reduce the repeat failures, what more and more professionals are finding out is you must replace the perfectly good battery at the same time. They will often work fine in older pre-1987 cars, but as they age, they lose their ability to dampen and absorb voltage spikes. Due to their design, these generators develop a lot of huge voltage spikes that can interfere with sensor signals for the many computers, and those spikes can damage the diodes in the generator.

Use an inexpensive digital voltmeter to measure battery voltage while the problem is occurring. It must be between 13.75 and 14.75 volts to recharge the battery and run the many complicated, unreliable computers. Based on your observation of the headlights dimming, you're going to find closer to 12.6 volts or less. Replace the generator and the battery.

Caradiodoc