Re-Engineer Two Automotive Circuit Boards to Output Ground Signal -- 2

I need to ship you these circuit boards for diagnosis. I have an OEM gear selector for an ICE powered car. It has 5 buttons and associated LEDs. It normally outputs a CAN or LIN bus based signal. But I just need it to output a "to ground" signal from each switch. What I would like to do is ship you the circuit boards and a spare connector with the pins. I need the LEDs associated with each of the 5 switches to illuminate when each switch is engaged, and the unit sends out a “to ground” output from each of the 5 functions, via the connector leads in the attached image. I tried to just solder on leads to the switch contacts of the larger board, but the leads and solder would not adhere. One can see in the image where the large board was burned at the unsuccessful soldering of leads. It would be great if we could turn off the previous function when switching to a new function. So for example, when in Drive and then switching to the Park position, it will automatically disengage the Drive function. I can do this with relays, or if you can come up with a robust automotive design to do this, we can discuss that function as well. I prefer not to use Arduino for this function in an automotive unit. The successful bidder will ship me back, at my cost, the wired connector so I can just plug that into a brand new device to complete the functions above. I need to test your completed and wired new connector in the new unit to make sure it works successfully before final milestone payment. Any thoughts, comments, or questions please ask before bidding. Thank you.