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I have had a 95 bonny with 95k miles for 2 months. I have had an intermittent electrical problem with losing ignition/voltage dropping below voltage necessary to run. The engine will always crank though. When this happens the voltmeter dives down, but the battery, though old will still show 13 volts? I pulled out the ground buss by the driver seat/door and while running it is really hot. That will get cleaned tomorrow. Quite often failure comes when accompanied by power seats or windows being activated. I have a load tester and the battery passes every time. So here is a question about the fuel pump. Where does the pump's negative attach at a buss?
As for the battery, it cranks well and seems to hold a charge with good voltage. The alternator seems to charge except when it is not getting 12? volts through the ignition circuit. The dash gauge will be in the red yet battery and bat post on alternator show 12.5 plus volts and motor spins like crazy. . Could this be a fuel pump failure?
I ordered scanning cables but since cleaning terminals check engine and anti lock have cleared. Problem with low/neg charging persist with a/c, lights on. Will check negative busses tomorrow. Thanks, Bert

UPDATE!!! Thanks all for the help. I have discovered the design fault on our alternators. Most have 2 or 3 wires controlling them. Mine has 1, telling the alternator to turn on. Coming through the ignition it has to have 12 volts otherwise it heats up and burns out the alternator as if less it will not release current. Most have the volt check coming from the battery and on from ignition. Another 95 bonneville design mystery.
The 30 amp fuse looked like it had chicken soup on it. Filing and a new battery solved it. Battery voltage is critical must be 12 volts plus through the ignition to alternator. Also there was a ground buss issue at the drivers door. It was burning red hot too. Bad damp connection. Possibly the fuel pump was on it? There were 6 wires, two fairly large being served. I think 4 or 5 had been rerouted to the footwell from above the foot brake only to return to another body ground 6 inches away.
I still have a 1/2 volt drop due to a bad ground going to engine. Once I get my ramps back... Also there was corrosion under the cable connectors on the pos side. 1 inch trimmed off the boost cable and alternator cable solved it. A new one is 25 bucks at rock auto. I had clamps. The cable to the starter cranks great though not pretty.















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How are your battery cables? Keep in mind corrosion could have made it's way up behind the insulation of the cables.

The pos looks ok. the voltage at pos alternator post is fine. Now the IAC is cycling with the ignition off.

Sounds like a bad connection somewhere, check all your grounds inside and out. Disconnect your battery cables and test the cables with an ohm meter from each side of the cable. You can have someone move the cable lightly while testing to see if you have any breaks. Check fuse center and firewall main junction connections too.

Also be sure to check for corrosion and tightness at the main wire that runs up to the Maxi Fuse Center.

I had similar behaviors in the Regal when the wire that feeds the same systems worked loose.

I have found something interesting. 5 ground wires that might have terminated above the footbrake appear to have been cut and appear to have been rerouted to the bus under the carpet at doorjamb. There are 6 wires black coming from firewall. One would serve the bus, with 2 clients. I assume lights, ignition? and climate control or radio could have been rerouted there. Really bizarre since the new extensions to the bus return back to same location inches from other discarded ground lug? Might help explain the extreme heat I felt. Does anyone know where the fuel pump negative wire terminates? Thank You!!!