Old School Troubleshooting

My 01 Monte wouldn't turn over after work the other day. Got it going with a jump start and drove home. I let it run in the driveway for a half hour, shut it off waited five minutes, tried it again and it started right up. Next morning, it was dead again.

Now for the troubleshooting part:

When I was a kid and worked in a garage, the easiest way to troubleshoot this problem was to jump start the car, park it inside the shop and turn on the head lights. If the lights came on bright and stayed bright when you turned on the wipers, A/C fan and every other thing, the battery was bad. If the lights dimmed as you turned on all the accessories, the alternator was bad.

So I did the same thing this time and concluded the battery was bad.

Now, when I think about it, I wonder if there is some gizmo in newer cars that would invalidate this procedure.

Am I crazy?

Wow! Pretty involved procedure there... It does sound like a bad battery, but you can't tell for sure yet.

Advance / Zone will load test it for free. Other diagnostics, like finding a drain / draw on the battery is up to ya'. A new battery will help that for 3 days. Then you got the same problem...

My 01 Monte wouldn't turn over after work the other day. Got it going with a jump start and drove home. I let it run in the driveway for a half hour, shut it off waited five minutes, tried it again and it started right up. Next morning, it was dead again.

Now for the troubleshooting part:

When I was a kid and worked in a garage, the easiest way to troubleshoot this problem was to jump start the car, park it inside the shop and turn on the head lights. If the lights came on bright and stayed bright when you turned on the wipers, A/C fan and every other thing, the battery was bad. If the lights dimmed as you turned on all the accessories, the alternator was bad.

So I did the same thing this time and concluded the battery was bad.

Now, when I think about it, I wonder if there is some gizmo in newer cars that would invalidate this procedure.

Am I crazy?

your not crazy on this technic..but this is a good start to finding the problem.

lately I have been doing many alternator/battery repairs that are odd.. like the shorted battery...this had me going for a little bit..

with my simple test equiptment I check the battery for voltage under load and charge and see if its responding ...then check alternator diodes and resistance...

If the lights dim under load engine running I would measure the alternator output current and voltage...

with that there is no question as to whats acting up...don't want to put a new alternator in with a shorted battery..


did a lot of alternators this year...