Recently changed motor, Now my problem is the ecu is not getting power and the brake lights stay on as if i have my foot on the brake. I have all power to radio and dash but no ECU or fuel pump. I have double checked all my wiring and grounds, changed bcm, ecu and ignition switch. Its a Ls 3.8. Any suggestions or help???

 

Have you checked your relays? Maybe you blew something when you hooked everything back up?

Did you double check your wiring with a multi-meter or just visually?

Relays and Fuses would be the first place I would look.

 

Reminds me of when I replaced a transmission and upgraded some suspension parts.

I blew my horn fuse at some point... never expected that - and only found out after I failed state safety inspection.

 

If you didn't do any work under the dash the disturb the brake switch, maybe a ground was left off when the engine swap was performed and power is somehow backflowing through the brake lights. Check to see if all grounds were reconnected.