The check engine light is the SES it has an entire separate bulb socket that you disconnected at the dash. Those two wires attach to the wires on the socket. Either cut or splice in.
And the seat belt has a dedicated ground just for the seat belt it is in the C1 connector. That ground goes to the chime module and the seat belt connection by the seat. The chime will not come on if the seat belt is fastened. If you ground it to anything else it will never work.
This is a pretty hard install for a non electrical person if you have a friend that is good with car stereo or stuff like that see if they would be willing to help.
And the seat belt has a dedicated ground just for the seat belt it is in the C1 connector. That ground goes to the chime module and the seat belt connection by the seat. The chime will not come on if the seat belt is fastened. If you ground it to anything else it will never work.
This is a pretty hard install for a non electrical person if you have a friend that is good with car stereo or stuff like that see if they would be willing to help.