Quick Question about Negative Battery Cable. . .
 

Is it mandatory to disconnect the negative battery cable before removing the alternator? The reason why I ask is because the battery on mine is underneath the back seat. :?

I would be inclined to lift the battery positive at the battery. That way you're removing battery potential to ground at the alternator terminal while working the alternator. Lifting the battery negative doesn't really help you. Does that make sense?

I suppose so. . . it's just that AllData said to unhook the negative side for some strange reason. :?

Yes, the negative is always the cable to be removed before any work is performed. It is not suggested that you work on your car or alternator for this matter w/o unhooking the battery. The most it does is cause you to learn how to set the clock. (I'm VERY good at setting my clock... :lol: )

Look at it this way Mac.. if you take a moment and unhook the battery, you won't be able to test if your fillings light up when that tingly feeling of electricity passing through your body occurs.

Be safe..unhook.

Unhook both. The charge lead at the alternator is hot off the positive terminal from the battery.

And it only takes like 30 seconds to lift up the seat to get to the battery.

but if you disconnect the negative; that hot lead isnt so hot under the hood, the nearest discharge location is under the seat

and for the record, it takes about 4 seconds to remove the back seat, and 10 seconds to put it back in.

Well.....which ever way you want to do it. Positive , Negative or both. The bottom line is that you are placing the battery on open ckt. Sometimes the books aren't always gospel. In this particular scenario there are two different (maybe 3) schools of thought, neither of which are wrong.

Thanks for all the help fellas, I'll go ahead and unhook both cables. :D

I once didn't unhook the negative when pulling my alternator. The power lead hit the body of the alt, which rubbed the accessory bracket as I lifted it, sparks flew, ring terminal arc welded to the body of the alt, insulation on power lead was cooked and smoking.

So I ALWAYS unhook the negative.

It sounds as if you didn't have either positive or negative disconnected if you had sparks flying.

I have done the same thing as J Wikoff. I got so used to changing the alt on my Lumina all the time that I flat out forgot to take off the neg cabe once. The sparks let you know you forgot!

i believe thats what he meant...

the negative is the preferred to be unhooked because you have a MUCH lesser risk of shorting out while unhooking it... If your taking off positive while the negative is connected, it is very easy to swing your wrench into ANYTHING metal and cause a short

Hence the reason why GM installed an out of place looking piece of plastic on the radiator support right in line with the battery terminals on the 92-99's.

I didn't unhook the battery cables when I changed a starter on a Cutlass once. I was a teenager and just forgot. Caught the car on fire. That was fun!! I'll spare you the details. Lessons learned.

X2

When I did my LIM ect, I had to remove the alternator. The negative cable was removed and nothing arked or grounded out, even when boosty touched the alt wire to the car. so im willing to bet, you will be safe just removing the negative cable. ;)

Just negative removed is all you need. There is no way for the battery to make any current or voltage if there is no connection between terminals.

Yes, I can't dispute that. I'm old school, I've always used wrenches wrapped in electrical tape or insulated when working batteries. I'm holding the line on the positive disconnect. From a technical standpoint it makes no difference.