wiring routing

I have a 92 318i convertible. ( this is an M30 as convertable did not change till later.) I am baffled by a lighting problem. My left front parking light and turn signal have stopped working. I checked bulb, socket and ground and all are good. According to the wiring diagram there is nothing in common but the ground to these circuits. The curve ball is there is an aftermarket alarm in this car tied into wiring some where.

I removed panels under steering column and still can't easily see where these wires go through the fire wall.

Does nay one know how these wires are routed under the dash.

RR