Expert: Roland Finston - 9/15/2011

Question
QUESTION: 1997 Chrysler Town and country LXi 3.8 V6.  Driving down the road today my van cuts off, coasts to a stop.  Battery dead.  Used a emergency jump kit to drive home.  Alternator grounding wire melted off at the mount point to the alternator housing.  Would this be caused by a bad alternator?  Or do I have another wiring issue.  Side note: 1 week ago I installed an aftermarket stereo head unit.  But it is the same power RMS output as the stock head unit.  

You have been very helpful, with my previous question about the p1494 issue.  THANKS!!

ANSWER: Hi Geoff,
I would believe that the alternator shorted to ground which resulted in the battery discharging through that wire which melted. The '97 manual mentions that the alternator is 'case grounded through its attaching bracket' rather than there being a grounding wire. So it may be that the wire that melted off was rather the + wire from the battery to the generator (which is black/gray in color) but in any case I don't see a basis for the generator itself melting that wire unless the wire was shorted to ground somewhere along its pathway back to the battery from the alternator. Interestingly you should find a dark green fusible link near the box attached to that wire from the alternator back to the power distribution box which I would believe should have 'opened' rather than the wire melting if the alternator shorted to ground. So I would examine the black/gray wire between the alternator and the fusible link to see if it might be open and one end of it shorted to ground as well. The fusible link one would think should have prevented the wire from melting.
Roland

---------- FOLLOW-UP ----------

QUESTION: .  It actually melted at the point of contact with the alternator.  I traced the wire to the negative post on the battery.  I can't see a fuse able link on this wire.  Should I strip the insulating wrap to see more of the wire?

Answer
No, the fusible link is on the + wire, not the grounding wire, which I don't actually see in the '97 wiring diagrams. Assuming that the alternator is not case-grounded but actually grounded by the wire that burnt, I would believe that the alternator shorted to that wire internally and the battery then burned it up. But I would have thought that the fusible link would have blown. In any case, you should show there to be 12v coming from the battery on black/gray wire if the fusible link is still functional.  I don't see how the alternator, other than by shorting the battery directly to the grounding wire, would burn through the wire so the alternator is probably no good. Check to see if there is a short between the gray/black wire and the grounding wire.