I was driving with my girlfriend in her `91 volvo 940 turbo, on our way to pick up my cherokee from the exhaust shop, when it started acting funny. The interior lights got dimmer and dimmer and dimmer. The power started fading. It started sputtering at idle. And then it died. We pushed it to the side of the street and hopped in a cab to get the jeep/tools. Then drove to auto zone to get a new alternator.

Installed the new alternator on the side of the road. The install was pretty straight forward EXCEPT that main post for the power on the new alternator was a lot bigger than the main post for power on the old alternator (10 mil vs 13 mil?). So I cut the terminal loop on the wire and spread it out a little bit to fit over the larger post. Buttoned everything up, tightened the belt, reconnected the battery, and tried to start it. Nothing.

So I pulled the cherokee next to it, and hooked up the jumpers. I hooked pos on the jeep, pos on the volvo, neg on the jeep, neg on the volvo (both cabled battery to battery, none grounded to frame) and let it sit for a minute. In that minute the cables got *Smoking* hot and completely melted the rubber casing at all four ends. We never cranked the engine, nothing... just had the two batteries connected.

After pulling the cables, I double checked the wiring for the alternator (I don't know why this would matter because the alternator wasn't spinning), checked that the cables werent crossed positive to negative (By checking markings on the batterys, not by wire color) and tried again with a second set of cables. Again, they starting smoking/melting immediately.

I've never seen anything like it. What in the world would cause something like this?!

 

Sounds like a dead short in the new (rebuilt?)alternator. The fact the wire didn't fit might indicate it's the wrong alternator or another problem. I can't stand when "exact replacements" are not exact. You shouldn't have to modify the cable terminal. If you have a multimeter check for a dead short in the alternator.

 

Firepop - you're dead on.
The alternator (I assume rebuilt b/c it's from autozone) was supposed to have a plastic washer that isolated two of the wires from the alternator casing. For whatever reason, it wasn't there (Thanks autozone), so the power wire was grounding to the case. Dead Short = hot jumper cables.

Thanks!

 

Now class... Say "Thank You Communism"

Ahhh China... Aren't they great.

Someone somewhere doesn't give a crap that they could have started your car on fire....

 

Rebuilt parts frequently aren't rebuilt well. Recently replaced a leaking rear caliper on a 2006 mustang with a rebuilt one that actually leaked worse than the one it replaced. I once changed a steering gear on a Ford van with a rebuilt unit. The job went smoothly, but when you turned the steering wheel to the left, the wheels turned to the right!!!! I assumed I did something wrong, but it was shoddy rebuilding. Nothing like doing a pain in the *** job twice. If the price isn't killer, new parts are sometimes the way to go.