1992 Lexus GS300 Hooked up battery backwards.?

It depends on how your electronics were made in the first place, but you will be lucky if it starts at all. You can actually cook everything from the alternator to the starter to the main computer this way, you must never ever reverse the polarity like this and hook a battery up to a car. I believe you are headed for a shop, i THINK i WOULD CALL A DEALER AND ASK AFEW QUESTIONS ABOUT WHAT ACTUALLY HAPPENS.

If you've a 12 volt test probe you could ground the probe negative clamp wire to the negative battery post or chassis/frame/ground then use the test probes tip to puncture the wire before the in-line/fusible link and if the probe lights up you know the wire going to the in-line fuse is getting power, now try the other side of the fusible link.If no power there double/triple check the test and if for sure no power then the fusible link most be blown.

Cables/wires you'd want to test are the main positive wires/cables running from the positive battery post to places like the starter/starter solenoid , power distribution centre, alternator and make sure none of them or the negative engine block ground cable is melted or damaged or fried/burnt.Note that in cases where a dead short like that occurs the weakest points will go , this means that even if the wire has a fusible link in it that may not be where the wire melts/fries etc.

My best advice in order to be able to fix that problem is start with the obvious fuses that you known have blown then if you had diagrams/schematics and the fuse chart you could find out what fuses feed other fuses and what main feed wires are connected up to them or feeding them.For example the stereo has one constant positive 12 volt feed this feed is fused and usually it's connected up to a fuse that feeds other constant circuits like a cig lighter.This fuse is a lower amp fuse like 10-15-20 amps all depending on what all it feeds and then a higher amp fuse such as a 30-40 amp fuse may feed it.The stereo also has a second feed coming from the ignition and that circuit has a fuse before the stereo usually in the fuse box in the car, but it also may be fed via another ignition switch feed that uses it's own fuse. Note the ignition can have fuses both before the ignition/ignition switch feed and in the output parts of the ignition switch.

The problem here is you may have blown the voltage regulator and it's either located inside or on the alternator or externally or inside a comp such as the ECM. This one more reason to have diagrams/schematics on the power distribution centre, fuse box, alternator/charging system/ battery and radio.Note that you maybe lucky and all that is blown is the fuses for the alternator and radio but usually the part where the fusible link is is quite tough and hard.I'd try checking that fusible link , changing the fuses but check the cables/wires closely before reconnecting up the battery or trying to restart it.




Hope that helps and best of luck.By the way places like autozone.com offer free print outs of different vehicles circuits and if you register online for free and look up your vehicle, then click on repair info, repair guides/schematics you may find diagrams to can download for free. Also places like part source offer free print outs on the spot just be sure to get enough diagrams/schematics that you need.It sounds like you do have some basic knowledge and can at least test and find the problems yourself but if you do need someone to take a look at some diagrams/schematics and read or help guide you in trouble shooting you can feel free to contact me.