Low voltage problems

[o5iiawah]

I just bought a 94 XLT 4x4 and I've been having a ton of problems. The truck made the drive from Fort Pierce, FL to Gainesville the first night but has been having serious problems since.

While I am out driving all of a sudden turn signals dont work. Test wipers, they dont work. Engine light comes on. Rev-counter stops working. I limp the car home and throw a meter on the battery: 7.4v. Seems like a textbook alternator. I throw the battery on a trickle charger overnight and in the morning, its back up to 12.6. I get the truck running and pull the ground off the battery and the car instantly dies.

After swapping out the alternator, the car will run, but it seems the alternator is only putting out 11.9v, enough to run the engine and lights. Same deal as before - if I pull the ground off the battery, the truck dies

First, will pulling the ground off the battery cause the car to die? I know some cars will continue to run 100% through the alternator output. Im not sure if there's a seperate bus that hops right off the battery that runs something critical or not.

I am on my way to get the battery tested to see if by chance there's a bad cell causing a drain. Once I prove the battery, i can grab the codes and post them.

Some help would be unbelievably appreciated

 

[o5iiawah]

Fixed!!!!!

Took it to an alternator/starter/electrical shop. The guy tested a few fuses and found that the interior fuse panel (which runs the wipers, blinkers, mirrors, a/c, etc) was not getting power. When that happens, the check engine light grounds out and illuminates.

He took the harness off the alternator and cleaned out the plug a little bit.

General Sherman fired right up and put out 13.9dcv. All electrical systems are go. happy day!

 

[nexis]

Some advice for ya, Those battery cables are known for corroding from the inside. You said that you checked the voltage so I'm gonna assume you have a multi-meter and know how to use it. What your going to want to do is pull the positive battery cable off of the battery, and pull the output cable off the alternator. Check resistance between the two. Should be almost zero, but if you want to get technical, the resistance and voltage drop on good copper for the length of wire there is .0013 ohms and -0.13 volts. If you test it and its junk you have 2 options, goto a auto parts store (napa can get them in 48 hours) and order them in, or goto a auto-parts store and have a comparable cable made up on the spot.

I prefer to make my cables, because you can run bigger wire to the starter and alternator, and use military spec cable ends, which makes it a hell of a lot easier to add extras to the truck later on, and if you cook one of the wires, you can replace them super easy.