Corsica Alternator odd problem? ...---...

I offered to help the girl next door replace her alternator on a 1989 Corsica 2.0L air conditioned. A simple job turned into a nightmare. 3 alternators and two batteries later the car still isnt charging. Ive checked, and cleaned contacts and checked continuity of the fusable links between alternator and the starter even ground continuity. Have checked alternator, battery, belt, fuse port 4 and 9 and wireing. Ive replaced many alternators before never had anything like this its crazy. Im a Geo Metro fan and never ran into a problem that stumped me like this. Is there anything odd or quirks I should look for in the Corsica charging system. Help this thing is eating up days.

Are you SURE it is not charging? Have you had a meter on it to see what the alternator is putting out, or had it taken (if driveable) to Advance or Autozone for testing? A simple mulitmeter can tell you if it is putting out voltage, say 13-14 volts. If you are going by the fact that maybe the car won't turn over or turn over well, it could be something like a bad starter. My dad's car had this problem just a few months ago. Is the car truly not charging, or not holding a charge, or just not turning over motor? What voltage is the battery showing when not running, vs running? Advise as much informationa as possible. Perhaps others here can help with additional information if I can't. (I have not seen any other problems cause this)

Shes definitely not charging. 2nd new alternator checked at Autozone and NAPA also new battery. Alternators bench test good but car tests as not charging on Bear test equipment. Starts and runs perfect off battery. Using multimeter battery 12 VDC and constantly runs down over an hour with lights on to about 9VDC car spudders and dies. Ive cleaned all contacts checked fusable links between starter and alternator no sign any charging. Battery light is on but goes out when alternator is unplugged. Car stats and runs perfect when battery is full charged. Running atarts at 12VDC constantly drops not running 12.5 VDC. Really stumps me. Thanks

Just for the heck of it, take one back to where it was bought and have it tested. These places but their alternators rebuilt, maybe there is a problem with them rebuilding wrong. Maybe someone else has some experiance with this. I have never had this problem. Corsica's are infamous for alternators going out, but unsure what else it could be. I will read my 91's GM manual to see if anything else is mentioned...

Yes 2 altrenators were tested. Both tested dead on the car with a Bear load tester and bench tested okay. Ive almost ruled out alternator or battery failure because alternator and battery are brand new tested and retested. The alternator turns on or off internally based on demand from a wire to the starter that connects to the battery via the high amp output lead. Ive checked the demand line and it reads directly off the 12 VDC battery line at the starter and shows continuity to the alternator plug. In addition there is 12 VDC at the field coil connection so physically the alternator is generating current output as the magnets spin through the energised field coil so current is available. So far Im totally baffled my only concusion is there is there something else Im not aware of casuing the problem but have no idea what. The car wiring is in excellent shape with with no signs of rework or damage and passes voltage and continuity checks. Another form member Rottweiller28 had a similar problem and found it was corroded starter wiring. I checked this carefully physically and electrically it checks out. Thanks for your help.


End of the Problem. If you replace an alternator on a 1989 +/- Corsica 2.0L and you still don’t get it to charge. Rottweiller28's article he does an excellent job explaining and saved me allot of trouble. I had the same problem more hidden. Check fuses 4 and 9 (in cab fuse block) clean any signs of corrosion or replace check continuity even if they appear good. Then get a wiring diagram if possible of starter/ alternator electrical. Check the black wire/red stripe from alternator BAT terminal (large terminal with nut) find the black/redstripe wire at the starter (it is fusible link C on your diagram, starter on the 2.0L is right down in front behind the manidold easy to reach). If you look at the diagram both points should have the same nominal voltage as the battery. Check the starter end then the BAT terminal end for the same current as across the battery terminal. Each end should have the same nominal 12 +/- VDC reading. Don’t rely on continuity check as even a strand will check good for continuity look for the actual voltage. If you don’t find the same voltage on both ends its likely the fusible link or wire itself corroded,. blew or separated inside insulation possibly inside the harness. If you can’t repair it you may have to get a fusible link like I did, and 3 feet of 10+ gauge wire and a couple connectors and rewire it. If in doubt or on the road with limited resources jumper the starter to alternator. You will instantly hear the alternator trigger, lights will brighten, and your voltage across the battery terminals will jump to 14.5 volts. Thanks for your help this really baffled me. Corsica’s are to rough for me, I’m heading back to Geo Metro country and call back home to California on my Echolink Handy Talky and have a ice cold brewski. Thanks guys couldnt have pulled it off without your help!