I have another electrical problem with the same car I posted with the problem charging the A/C and the problem with the hot terminal on the heater switch. This is a 1972 project car I bought a while ago and now I'm trying to sort out a number of problems left by the PO. The charging system seemed to be fine until last night. I drove the car for the first time last night and it's having the common problem of very dim dash lights. The headlights are a little dim too. It has a newer transistorized voltage regulator and 60 amp alternator. I spent the morning cleaning the ground connections, the connections going to and from the alternator, and I hooked up a ground wire between the negative cable and the chassis because it had none. While I was at it, I decided to replace the voltage regulator with a correct AMK unit I had. I double checked the wiring before hooking everything back up and when I attached the negative cable to the battery, the voltage regular began to smoke (and the key was not on). I tried it several times and the same thing happened. Since this had not happened with the old voltage regular, I swapped them back out. No smoking occurred from the old voltage regulator when I hooked up the negative cable, so things looked good. The car started fine and everything worked. I wondered about the condition of the charging system so I decided to disconnect the battery by pulling the negative cable with the headlights on and the engine running to see what would happen. The car kept running but the headlights were very dim. When I reattached the negative cable, the headlights brightened. I checked this several times and it did the same thing. That surprises me, because I would think everything should easily run off the alternator. Why would hooking the battery back make the headlights brighter? Then when I disconnected the negative cable again, the car died. Why? Does anyone have an idea what to do next?