98 Lumina LS / 3.1, purchased new, has 84,000 miles. Intermittently losses all electrical power when the ignition key is placed into the ignition and the lock cylinder is turned from the on position to the start position. When this happens, all electrical power is lost, as if the battery was disconnected.. Tried using duplicate keys that came with the vehicle (Pass Key II), but nothing seems to work, until I attempted to jump the battery. Once I connect the hot jumper cables to the battery of the Lumina and turn the ignition on, I can hear a relay or switch click in the dash were it meets the steering column, at this time power returns to the vehicle and it wil then start and run fine. The vehicle gives no advanced warning when it will repeat this loss of power. The security light never comes on; the vehicle just loses all power. This only happens at start, I have never had the problem when the engine is running. Any ideas? Thank You

Do you lose primary power to the headlights, etc too?

Check the connections down at the starter and at the remote jump terminal where you connect the jumper cable to the positive side....sounds like you have a problem with primary supply from the battery....ever try just moving the wires/cables related to the battery and starter when it happens, see if it pops back to life?

Thank you for the reply. All power is lost, including the Hdlts. When power is lost, you can hear a very faint chime when the key is in the igniation and the door is open, other than that everthing else is dead. I checked all the connections & terminals when this problem started, all seem tight and in good condition, including the battery cables themselves.

Sure sounds like a loss of ground....might wanna take the battery connections apart and have a look...

Could just be a bad battery I had a similar problem with a 94 camaro I couldnt figure it out & took it to a mechanic ende up being the battery which was only 4 months old.

check them connections!!!! at first i was thinking the ignition switch but all seems well