I came across these Forums recently when I was replacing and Alternator in my 97 Mercury Sable DOHC
Duratec engine. I was driving home one day and noticed smoke coming from the engine, I pulled over, stopped the car and lost power.
When I checked it out, I discovered that the back of the alternator was completely melted, all of the cabling around the alternator was melted and shorted and the positive battery cable was melted. There is a picture of the bad alternator below.
I replaced all of the bad cabling, and the Alternator. Now everything seems to be running ok, The voltage is ok at about 13.8 volts.
My problem now is that the cable going from the Alternator to the battery is extremely hot, it seems like it's just going to short out again if I leave it running too long. I'm wondering if there is still some underlying problem causing this. The rectifier and regulator are built in to the Alternator, and the whole thing has been replaced.
I disconnected the alternator from the battery and checked it's output voltage with a voltage meter - one end at the battery negative terminal, and the other end at the alternator cable disconnected from the megafuse. The output measured was 40 V DC
which seems way too high, but it's a new alternator.. could there be a grounding issue ?
The only other thing that could possibly be related is that I replaced the Battery 2 months ago, it has 36R72 - previous battery was a UL-58R.
Any help or suggestions are greatly appreciated.