1999 Pontiac Bonneville SE, Cranked then went dead, all lights on dash blacked out, total loss of power, 3 seconds later everything came back. Noticed the positive lead that runs to fuses above engine where relays are was smoking and hot to touch. Checked fuses all were good. However not sure which relay if any I should check. Also checked grounds under hood for any looseness or corrosion all seemed well. Any ideas? What could be causing this wire to get hot.

Replaced that lead with a new one, no more heat, I guess it was just too corroded. I did clean up a few of the grounds, but they didnt look bad to me to begin with. So anyhows so far so good

its great when an issue is only an easy fix away.

That lead usually has a fusible link on it. I've had one go before. Sometimes all the fusible link is, is a thinner section of wire spliced in.

The problem is right where the cable got hot. There is resistance at the connector. Clean it up and make shure the cable is tight in the end.