FLHP: See Figure 1. The jack is on the back of the headlamp nacelle below the left side of the handlebar clamp shroud.
FLHTP: See Figure 2. The input jack for the public address (PA) microphone is on the left side of the storage box.
Figure 1. Microphone Input Jack: FLHP
Figure 2. Microphone Input Jack: FLHTP