I can help with some of this. Use a relay for the horns and aux lights, the ST2 doesn't draw much so you won't need a relay. The fellow that operates Eastern Beaver is good and I'm sure an email to him might get you a lot of the info you require. Just curious, the harness you have is specific to an FJR? Not making any assumptions is all. EB could likely help you with these connection points as well. Hope this is of some help.

 

Thanks for the reply. Yes, I have been corresponding with Jim Davis at EB and it's for the es 2019 model. Even took pictures of rear light snap to confirm.

 

The connector under your seat is for the OBD/dealer computer connection. Do not use that for anything.

The harness you have looks like it has a relay in it..... necessary. Hook your battery tender cable direct to the battery and store it up front. Do not remove the fuse.
Horns - depends on the total draw... if 5 amps or less, can use existing wiring. More than that, relay recommended.
Aux lights - same kind of guideline, but optional. I tend not to, but fuse them via the aux. fuse panel.
Heated gear - likely won't draw more than 10 amps.

What is a "snap"? New term to me for electrical.....

 

Thanks for the input. The "snap connectors" I am referring to are blue arrowed. I think one is switched and one is not but again, I don't know which is which, or what connects to them.

 

Can't help you with the wiring loom and where it would plug in, EB will need to do that. The only relay needed is the one in the loom, for the switched circuits. The PC-8 is rated for 50A, 600w @ 12V. Not many bikes (if any) can support that draw. Use larger gauge wire for hi current, ie heated gear and possible acc horns, to prevent voltage drop and heat, then just use the appropriate rated fuse for each circuit. Small draw items can be combined if needed. I used either 12 or 14 gauge braided wire for heated clothing, can't remember. Home thermostat wire comes with varying # of wire pairs and can easily power things like a gps, radar detector, phone/usb charger etc. and the sheath provides for a nice tidy install. Spool up the unused wire pairs for future additions. It is small bell wire that is easier to deal with vs small braided wire. I solder and heat shrink all connections except the posi-tap for the switched relay - years of weather and vibration on a bike mount is tough for solderless crimped connections, and you don't want to strip all the tupperware to get to a connection in the middle of nowhere.

The end of any braided wire should be tinned with solder - this helps with the connection in the PC8 terminals. The bell wire doesn't need it. Larger gauge wire may need to be trimmed to fit into the PC8 terminals - the full gauge of the wire is still used to carry the current.

FJR - is there a place to locate the PC8 close to the battery in the fairing? Since most or all of the wiring will be up front, it would make shorter wire runs if it's possible.

I've installed 6 or 7 PC8's on my bikes over the decades. Here's how my current four bikes are wired, by circuit:

Unswitched:
SAE connector for trickle charger
GPS

Switched
Heated jacket liner and gloves
Radar Detector
Usb charger
Driving lights (low amp LED)

 

The end of any braided wire should be tinned with solder - this helps with the connection in the PC8 terminals. The bell wire doesn't need it. Larger gauge wire may need to be trimmed to fit into the PC8 terminals - the full gauge of the wire is still used to carry the current.

Tinning with solder is a proved, good option. Recently I started using another method that is probably more a bit more expensive, but I think it is neater and faster: ferrule terminals. The ferrules themselves are not expensive, but using them require a special crimper (I got mine from Amazon). The photo below shows the ferrules alone, a crimped one, and an installed one into the PC-8, using a 16 AWG wire. These terminals make repositioning wires easy.

 

I have wired up a few PC8's myself but did not use his harness, made my own with a relay.... No matter. I see you have it connected to the PC8, so you need to find the tail light wire or licence plate wire for a trigger circuit to activate the relay. The long wire going out of the picture is to your battery. Limited room to hook it up beside the battery, and a PITA should you blow a fuse on the road, so best under the seat or in the tail, leave enough wire on your devices should you need to access the PC8 and move it a bit to fix something. 12 ga. wire feed is what I think he supplies, hook direct to the battery, and see if he has a fuse in the positive.....

Still never heard of "snap" connectors... prefer to just call them connectors, to which one would plug in a mating connector..... OR, are those fuseholders?