You mean there is a longer than normal delay from when you change from Reverse into Drive?
I don't think that is an electrical problem. Problem is Auto transmissions are the hardest part to troubleshoot as there is a lack of information about them.
All I know is on the troubleshooting guides in many workshop manuals, under "Delay when shifting into Drive".... Remedy says "Overhaul Transmission"... However I don't know exactly what parts are defective and need overhauling/replacing.
Good idea would be to talk to a Transmission specialist, ask them questions so you can actually learn a bit about how the transmission works not just have them charge you money to repair.