Does the buzzer sound when the circuit is closed at the left door switch?
View attachment 1715880060
If not, then maybe its not connected to buzzer.
CI 5 is steering column connector.
Could be a pinch or a miswire there?
On the inside there's two wires for the start.
Ignition Start (J3) is Brown. That does not effect the starter.
Starter Relay trigger (S2) yellow. That does not effect the ignition.
In the engine compartment, for the starter relay to close, the neutral safety switch must ground.
The only way it could get involved with interior stuff again is getting cross connectec with those reverse light wires.
That is, unless something else was modified.
Might want to begin with the column connector, and then do some continuity checks to see what else may have gotten connected in to those circuits that shouldn't be.
View attachment 1715880063
Another check might be to disconnect the NSS wire at the relay.
Temporarily run a jumper to ground. See if it starts with the door closed.
if so, then you know it relates to the NSS wire.
