I have a 2000 Impala LS. Four years ago it would not start, dash was black, no dome light, just like the battery was disconnected. I wiggled the battery cables but nothing, then wiggled the wire harness below the battery and closer to the fire wall, it started working. This happened several times then it quit twice while driving at speed, pulled to side of road with no electrical power anywhere, wiggled the wire harness again and off we go for another couple of months. Dealer checked it out and could find nothing wrong. Checked the connectors in the harness and they look OK, clean with no corrosion. Two weeks ago at night the car started but the headlights were not on automatically, pulled the light switch on but nothing. Turned the car off but it would not start up again, then the dash went black, not even the dome light works. Wiggled the harness and off we go again. One week ago symptoms changed again, the radio, dome light, and door locks would not work, wiggled the harness and everything works again. I am an old electronics technician by training and this seems like a bad mechanical connection somewhere, but where? I thought about the Body Control Module, but it is under the left side drivers dash so how would wiggling the harness by the battery impact the BCM? Any ideas?
I’d stop wiggling the wires and figure out what’s really going on. You can’t drive a car not knowing whether it is fixed - that’s dangerous for both you and others on the road. Wiggling is not fixing.
Since the dome light doesn’t even work, there’s a bad connection between the battery and the rest of the car.
An easy way to make sure you have a decent ground is to use your booster cable and use only the negative (-) side to bridge connections that may be bad. Start bridging from the battery’s negative to a solid beefy piece of steel on the engine, then from the battery to the frame, frame to engine, etc.
One of those harnesses clearly has a bad connection. Start cleaning at the connections from the battery to the frame, to the starter, fusebox, etc. Also check the big ground straps going from the frame to the engine, transmission, etc.
You are correctly thinking that a bad connection is causing this trouble. I suggest you clean the battery connections and also the connection that runs from the battery to the main distribution panel under the hood. Clean the chassis ground from the battery also. If doing that doesn’t clear the trouble then check for voltage getting to the main fuse in the distribution panel when the trouble happens again. That should be the first place power from the battery ties to. If there is no power there then the other end of the wire needs to be checked for a faulty termination connection.
Hey JCB you by chance work in Savannah??