Larry,
Here's one for your "book".
As you know, the radio troubles I've been having on the 98. Codes didn't work first time. Radio "locked up". Says INOP. Called GM, they said turn key on for an hour. Told them with the day time running lights batt would go dead. They said, turn off driving lights and step on "E" brake. Lights would go out.
Didn't know that, did you? It worked. Something new everyday.