If you search "Porter Cable 892 wiring diagram", a schematic pops up. There is a common tie point for white (the power cord), red to the motor and blue to the speed control. If you have a multimeter (dmm), see if the blue and white wires are tied together in that block. Stick in the probes and it should read zero between blue and white. If so, leave one probe in and find anothet empty pocket or pockets that is tied to the blue and white. That is where the loose red goes. The black wire is not connected to the other three so there may be pockets you cannot use. REMEMBER, only pockets tied to the blue and white are good. There may only be one. The diagram i found shows how to bypass a bad speed control and the changes are in red but you can ignore that; you are not modifying your router. Unfortunately it is a schematic, not a pictorial which make it a little less convenient for those without an electronics background. This might be an area you are not familiar with but that is is the best I got. Hope it helps. There is always plan B; buy, peek and return. In the diagram, in the upper right you will se the tie point where the *********** cord wire ties to the red and blue
Sent from my SM-G900V using Tapatalk