Hello, everyone. I foolishly installed the battery backwards in my 02 Civic LX 1.7L. It's been sitting for a couple years and I forgot the correct orientation. The 80 amp battery fuse immediately blew. I replaced the fuse and it appeared everything was good to go. The locks, windows, headlights, horn, a/c blower fan, radio, and map lights power on, when the key is in the auxiliary position. Basically, everything has power. The fuel pump primes, too. All fuses under the hood are good. I did not check the relays, as I can't find schematics on them. The moment I try to start the car, power to everything is lost. It's acting as if the battery fuse has blown, but it hasn't. In order to get power back to everything, the battery must be disconnected and reconnected. Any ideas? Could it be a bad ECU or possibly something else? Any help would be appreciated

 

Are you still trying to use the same battery that you installed backwards ??? If so, you may have damaged a cell inside and it doesn't have enough power to turn the car over, but enough power to make things appear ok. Try another known good battery.

 

Installing the battery reversed there is so much damage that could have been caused, besides relays and fuses, you could possibly have damage your computer, the body control module.