I am sure this has been talked about before, but I am brand new to this forum and find it very interesting so far. I have a 1999 Bonneville. The other day it cranked fine but as soon as I put it in drive it shut down..everything! I only received the warning lights flashing, the radio lost all its programing and clock. After several tries it cranked and was able to drive it home. Last night, it cranked fine and started driving off and when I cut the high beams on, it shut down..just as before. After several cranks it started and I was able to continue my journey. Is it the battery? the alternator? some other problem?I have noticed the lights gets dim (a little) everytime the turn signals flash I fear it leaving me stranded on the road. I know of the alternator going bad and just shutting down everything. Thanks!

Try cleaning your battery connections.

But I always thoought if the alternator is working fine, you should be able to disconnect the battery and the car still run? If I have bad connections, shouldn't the alt. keep it running. Anyhow I will check connections tonight and thanks.

Well see, the thing is, that sometimes when the battery terminals or cable connections are corroded, they will cause ghost electrical problems. Often intermittently.

On another hand, have you been paying attention to your electric gauge while your turn signals are causing the dimming?

Do you have a multimeter/voltmeter? If so, try reading and following this simple diagnostic procedure. It doesn't cover everything, but it'* a good start and will cover 90%+ of most issues:

TheCarConnection Tip: Solving Electrical Problems

keeping my fingers crossed for it to be bad battery connections! The volt meter on the dash will ever so slightly move towards the discharge side each time the lights flash.

Try putting a volt meter across the battery posts. You should get about 14 volts if memory serves correct. That will tell you the condition of the battery and you can go from there.

definitely check those connections.

I remember that I didn't have my connections tight and my gauge and my lights would all flicker continuously...it was extremely annoying. check and clean for sure. that should help alot.

That won't actually tell you a whole lot. Even with corrosion, you'll still read the full potential. It'* the battery'* CURRENT delivery that is hampered by the increased resistance from corrosion.

Lights will work, starter and ignition won't (for example).

This issue resembles a loose or corroded battery cable. Check them all...both ends.

I had been saying that for quite a while ...and one day I took the advice. It'* much easier than it sounds.. or looks. Pull the rubber boots off the ends and look for corrosion.

okay, I went out tonight and checked the battery terms and guess what? The positive was corroded terrible. As soon as I touched it the engine shut down. I never dreamed that what was causing it. I was always told that if the terminals were bad, it wouldn't crank because the battery was there to crank it and the alternators job was to supply the electricity.

Many many thanks to all!