2008 Hyundai Elantra GLS. Battery went dead, jump started and afterwards these systems did not work: window switches, door lock switches, rear defrost, dash cluster backlights, trunk release switch. All other lights and switches worked. Reset ECM by disconnecting battery and draining capacitors. All systems then worked. Battery died again a few days later. Battery was bad on test so I replaced. Now those same systems do not work and the reset did not fix it this time. Bizarre clustering of systems - likely bad ECM or am I overooking something more obvious? (all fuses rechecked and are ok).
The Body Control Module may have to go thru a relearn/reprogram procedure.
https://www.aa1car.com/library/battery_disconnect_problems.htm
Tester
@Tester thank you. That seems to describe my situation. I think that means a trip to the dealer, but that is better than a new ECM!