I've got a 90 LS 400. After parking the vehcle and turning off the ignition, I couldn't unlock the vehicle. I put the key badk in, turned it, and the alarm went off. I shut it off and tried again. This time the cluster lights came on as usual but when I tried to start, it was completely dead. I tried several times and same thing. I checked battery terminals and they seemed OK. The lights, radio etc would work. I put the lights on, turned the key to start, and lights did not dim but no cranking or anything with the engine. I played around, shifting gears, etc and nothing. After about 10 minutes of this it started and I went home and haven't touched it in two days. The alternator is putting out 14 volts. My trac light has been coming off an on lately and was on when this happened. Any thoughts? First time on this site. Thanks, George P.

 

Welcome to CL. Sound like your driver door lock security wire is bad. There's a plastic cap with 2 wires attached to the end of your driver side lock cylinder. I think this plastic cap felt off or broke and the car's security system is turn on and cut off the starter.
Quick check, just lock your doors by using the passenger side lock. Wait for about 30 seconds to 1 minutes until the security light flashing.
Unlock the passenger door with your key( make sure the sec. light goes off), then start the car.