1990 Pontiac Sunbird Won't Start, no power

1990 Sunbird 80,000 miles (really). I had no prior problems to this. I was driving for about 25 minutes, city driving, with no issues. Stopped at a red light and after idling for about 10 seconds the car shut dow. No stalling sounds, just shut off like I pulled the key out. I have no power now except for the dome light. In any key position the lights, wipers radio, turn signals, nothing. When I try to start it I don’t get anything. Not a sound. Any suggestions?

How old is the battery? Losing all power like that could from a bad battery. Batteries can fail without prior notice. It’s happened to me. Working perfectly fine, and then dead without warning.

Tester

…especially if it is a maintenance-free battery.
That type seems to fail suddenly, and without any prior symptoms like slow cranking.

Thanks for the reply, but the batter was checked out. It’s fine. I should’ve put that in the original post.

Okay. The next thing to check is the positive battery cable assembly. Your battery has the side mount terminals. And on each terminal is a rubber cover that each of the little bolts pass through. On the positive cable assembly, corrosion can form under the red rubber cover causing a voltage drop.

To check for this, remove both battery cables from the battery. Take the positive cable and peel back the red rubber cover from over the terminals. If you find a white powder under this red rubber cover, that’s corrosion, and the positive battery cable assembly should be replaced.

Tester