Thank you for choosing JustAnswer and allowing me to help you resolve your Lexus questions!
WAs the car jumped backwards or the battery installed backwards even for a split second?
This means the 120 amp ALT fuse is blown. This is the linkto the battery from the ALT large post. This is located in the fuse box underthe hood. This is a large box type fuse. If it is blown open it has to bereplaced. IT is bolted into the fuse box. The fuse box has to be disassembledto replace it. If you touch the terminals together as a test see if it charges13+ volts. Let me know what you find.