Contour Enthusiasts Group Archives Forums General Troubleshooting scorched alternator output

Replaced the alternator in my 2.0L: 2 weeks later, battery light flashing.
Manual indicates a loose connection to alternator, so I tighten them all up.
Notice the alternator output connector (The big one on the red insulated post) is a bit loose and well corroded, and now quite a bit scorched near where the wires screw on.
Try to tighten that connection but battery is still not charging.

Question: could the loose/corroded connection itself cause the scorching? Or do I need to track down another electrical glitch somewhere?

BTW, it is not surprising that it was corroded, because I had to use the connecting post from the old alternator (the new one was shaped differently and didn't line up right to connect with the output wire).

Thanks for any input.

First off I hope all this tightening is taking place with cable to neg battery terminal disconnected.

Second have you cleaned off all the scorching/corrosion on the main alternator connection and the lug of the connecting wire?

Are you sure your post alteration is OK?

Are you able to get battery volts at cable that connects to alternator, i.e. 12 volts to neg bat terminal?

1. Yes I have a healthy fear of electricity and faithfully pull the plug before sticking wrenches back there.

2. It is beyond being able to clean - the nut got locked on and the bolt sheared off when I tried to remove it. That is the reason for the bad connection to begin with - the nut never got tight cuz it siezed onto the corroded bolt. It needs to be replaced before I can test it again.

3. Post alteration - it was the original post, ran for 65000 miles so it should be a good match - unless the parts folks sold me the wrong alternator. I will check on that on Monday.

4. I've got battery voltage at the two alternator test points ('A' and 'F') but I haven't tested at the output wire. Does that show 12 volts even when the engine isn't running?

I may have worded my last point poorly, it was to confirm that you had continuity on the main cable to battery. Since it was disconnected at alt. and neg cable (only) was off battery you would have to check from alt. end of cable to neg bat terminal to get volts.
Alternately if all was connected, and ignition off then you should be able to measure volts at alt. terminal, but of course this would be battery volts since alt. is not turning.
I guess my concern from reading initial post was whether you had experienced a short to ground at alternator output terminal or was it simply B+ arcing because of poor connection.
It seems you have diagnostics well in hand so we'll wait for your success story to be posted.

Good point, and just the sort of suggestion I was looking for. I did get battery voltage between the neg terminal and the alt. end of the cable. But also found a cut in the insulation on that wire, near the alternator terminal connection. Question is, cause or effect? But I figure if I replace the terminal to get a good connection, and put some heat-shrink and tape over the end of that wire, and replace the connector on the other wire that attaches here, I'll be back in business. Tough part is finding the terminal extension post, working on that today with the parts folks.

There should be a fusible cable link somewhere between alt/starter/bat, not necessarily relevant but FYI.