Lexus813

Hey am new to this forum and I have a huge problem.

i have a 1995 ls400

After i changed the alternator and installed the battery back the positive and negative contacts were loose and it looked like one got disconnected with the car running.

now the car starts but doesn't charge the battery, the A/c doesn't work and the transmission is locked. and every time i change fuse number 3, 6, and 9 they burn out.

What parts could of went bad when the battery got disconnected?

trukn1

Sound like you have a few problems here. You changed the alternator and now the battery isn't charging?? Are you sure the alternator was good when it went in? Was it new or a remaned? are you sure that all of your connections were tight and hooked up right? Not to brow beat you with questions, but these are some of the things that need to be ruled out here. Which terminal came loose with the car running? You state that one of them came loose, but don't specify which one. As far as the transmission and fuses, not sure which ones these are ( I had a 92) and don't know them off the top. I would check ALL of your fuses especially the ones under the hood, as it appears you may have blown one of the main fuses essential for the car. Sounds like the same symptoms as when people hook up the battery in reverse polarity. Check ALL the fuses first, not just the ones you have been replacing.

Probably just blew oneof the 120 amp fuses highlighted by the green section in this thread,,,,,this may help aid your search for the appropriate one blown.
https://www.clublexus.com/forums/ls4...ms-1990-a.html

mspearl95

could be a short in your alternator. take it back and say it didn't work. or at least have it tested.

oldskewel

iTrader: (1)

From direct personal experience with my other car (a 1985 Porsche 911), if the battery cable is momentarily disconnected, it can damage the alternator and maybe other stuff.

In my case, after helping a friend troubleshoot his 911, I started mine while the battery cables were pressed on the battery posts but not tightened. When I then connected a jumper cable, it must have momentarily opened the circuit between the cable and the post. The car died instantly. After tightening the cables, it started just fine, but something in the alternator had been fried and it would not charge. I ended up just replacing the whole alternator (on those cars, the voltage regulator is internal to it) and things were fine. In my research in figuring out if alternator damage were possible from this one incident, I found that yes it could be. The battery provides a ground reference that many circuits in the car use. If it is suddenly removed, the ensuing voltage spike can potentially damage many electrical systems in the car, even beyond the alternator.

I don't know what problems you have created, but I wanted to let you know that unfortunately a momentary removal of the battery cable can damage the alternator and beyond. Hopefully it is just a fuse, though. Good luck.

Yamae

Yes, oldskewel.
As is written at middle part of below page, disconnecting a battery while the engine is running can destroy sensitive electronic components or the charging system because the peak voltage can rise to 40 volts or more.
http://www.supercharge.com.au/battery_care_4.php

A loose connection of + side battery terminal behaves as if it is repeating the connection and the disconnection. Cars with a lot of electronics devices especially solenoids generate a big fly back pulse by this. As an engineer, I had been having hard times to design circuits to prevent the damages of the equipments that were shipped to auto manufacturers. Auto manufacturers test this but they don't do it too many times at the design stage.

Lexus813

Ok well so far i have disconnected pretty much every thing on the car and im still getting a bad circuit,
any idea what component could of gone wrong?

oldskewel

iTrader: (1)

Any chance the AC, AT, and fuse blowing problems existed after you replaced the alternator but before the battery post connection was opened?

It seems odd that a component failure could now be causing fuses to blow. I'd recommend starting by tracing those down to find the short circuit.