I recently bought a 02 gs300 and was replacing the battery and installed it backwards by mistake. Leading to no crank no start. Dash did not light up with the key in the ignition. Car ran before that, so I checked all my fuses both interior boxes and under hood. Found 2 bad fuses 1 40 amp fuse (I forget exactly which one) and the 120 amp alternator fuse. The lights on the dash work like normal normal now. Any suggestions??

 

I hooked up jumper cables to mine backwards once and it blew all kinds of stuff. cant remember exactly what it was, but there was some odd fuses one would not think to check. If you checked all the fuses already maybe try some of the relays.

 

This issue has been discussed at length in other threads. Should be easy to find.

 

I have found a couple threads but from their other problems they say they were having it’s not exactly unique to my situation. They usually started out with other problems before hand like already changing the starter or alternator from the get go and then having problems. I couldn’t find much when I searched the forum, any links would be greatly appreciated.

 

Take the ecu out of box and open it and see if anything is burnt or any capacitor is leaking.

 

Will do, I have to get back to the car to check tomorrow.

 

I've owned the car for a while now and realized those cars are built pretty well and tough for the most part. Its got to be some thing simple. If anything there's an ecu repaire service on eBay that restores your original ecu so you won't have to mess with immobilizer. I'm hoping that problem isn't your ecu. Keep updating.

 

Update got it running, it was a couple 15 amp fuses I found and replaced. I appreciate everybody advices

 

OP good news!

FWIW - pretty much any competent electronic tech can safely handle a PCBA, look for damaged caps, look up new ones and desolder the old / install the new. So don't pay a crazy price for the parts as they are cheap!!

If anyone is suspect of a an ECU cap failure, open and minding static discharge, take some good pictures and post them. A search for leaking capacitor will give people an idea of what they're looking for.