I put a new motor in my 2002 Honda Civic SI and cant get the battery light to go off. The alternator is working, had it checked. I've driven the car 100 miles day and night with no problems. I've checked battery connections as well as the ground cable and all is tight.

 

Definitely not trying to hijack your thread but I know these forums aren't as active as they used to be and am having the same issue, looking for some troubleshooting. I had an aftermarket alarm poorly installed and shorted out a couple things. Now battery light stays on. New alternator, battery, ELD, fuses are good, and hit everything in the charging system with a multimeter. Driven the car since October with it on and am just tired of seeing it.

 

Hey guys, I've had the same problem. I narrowed it down to the ecu. More specifically pin E24. Shows as SEFMJ. it's supposed to send the signal through the multiplex up to the gauge cluster for the light. It should test as 12v with the ignition on. Mine doesnt do anything and I haven't had anyone mess with there's to see how a good ecu tests. Figure the charging system checks perfect and works except for the light, so no reason to spend the cash to get a new ecu.