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Cleanly splicing into switched power on the R1200RT

Joe Frickin' Friday

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Joe Frickin' Friday

Based on helpful advice I received from folks here, I recently bought an Eastern Beaver PC-8 fusebox for my new R1200RT.


I made a bent sheet-metal tray for it and mounted the tray to a couple of handy threaded holes on the subframe just in front of the rear seat:




In this location, the 18" harness option was a smidge too short to route cleanly to the battery; I would recommend the 24" harness.


The harness includes a relay so you can get some of the circuits to switch on/off with the ignition key; all you need is to splice the relay control wire into a switched circuit on the bike. From advice I received here, I went to the rear accessory socket on the left side of the bike just under the rack. I offer some tips from my experience that may be useful for anyone else pursuing this option.


First challenge? Splicing some wire into the harness. The soldering is MUCH easier if you can get the harness off of the bike and onto your workbench. As it happens, this is possible: there is a short (6") cable that runs from a connector on the main harness to the back of the accessory socket; this can be removed completely from the bike, but only with some shenanigans.

The cable looks like this:




As you can surmise from this photo, the shenanigans have already taken place. The problem is that it's very difficult to remove the connector from the backside of the acc. socket, since the subframe is in the way. The obvious (but painful) option is to remove the tupperware in which the acc. socket is installed, but that's, um, painful. Far easier is to remove one single screw securing the tupperware panel to the subframe, and then flex the panel away until you can wiggle the connector free. That all-important screw is located right next to the backside of the acc socket. Peering into the cave under the rear rack, this photo shows the acc. socket with the cable removed, and the screwhole with the screw already removed (just to the right of the socket):




The connector of course has one of those PITA tangs on it that you have to depress whilst wiggling the connector free. Do this work with your left hand while flexing the panel away from the subframe with your right hand, and eventually you'll get it loose.


Once you've got the pigtail off of the bike, head for the workbench. Remove the fabric-tape wrap from the cable to expose the individual wires; save this tape to reinstall later. Brown = ground, so you want to splice into the [non-brown] wire.


If you're a neat freak, you'll want to put heat-shrink tubing around the connection you're about to make. To do this, you'll need to remove the multi-colored wire from one of the connectors. Grab the connector that plugs into the acc. socket, and clamp it gently in a vice. Take the smallest screwdriver you've got and stick it into one side of the connector near the weather seal, like this:




Pry to pop the connector apart, so it looks like this:




Once that's done, you can push down on the metal tang holding the colored-wire terminal inside the connector:




Pull/wiggle the colored wire while you're pushing this tang down, and the terminal should slide out along with the wire.


If you got too crazy pushing this tang down, you'll need to pry it back up to a useful angle before re-inserting the wire/terminal into the connector.


With the wire extracted from one of the connectors, now you can slip a piece of heat-shrink tubing over the connection you're about to make.


How I made the connection (sorry, no pics):


1. About midway between the two connectors, use a razor blade to scrape the insulation off of 1/8" of the wire. Use care to avoid nicking/cutting the copper strands.


2. strip 1/4" of insulation off of your new piece of wire; wrap this bare part around the exposed portion of the pigtail wire.


3. With the new wire held parallel to the old one, solder in place.


4. slide some heat-shrink tubing onto the wire over the connection, and heat-shrink it.


All done, you can re-wrap the original wires with the original cloth tape, so it looks like this:




Your newly spliced-in wire (mine is red) will of course hang out from underneath the tape as shown.


In that pic, the switched-power wire from the PC-8 harness can be seen below my pinky-finger, the blue wire protruding from the black sheath. It comes with a Posi-lock connector, which makes it easy to connect to your newly spliced in wire.



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Hi Mitch


Gret job connecting to the accy socket harness, looks awesome.


The only caveat I would have is suggesting folks remove the pin from the connector to install the heatshrink. Most will have trouble with this operation to the detriment of the pin and plug. Carefully cutting the wire and then reconnecting and soldering three wires is a better solution IMHO.


3M Temflex 1755 fabric tape is almost like the BMW OEM harness tape.

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Great Job, good pictures and instructions.


Next time you have to splice wires or T into wires or connect multiple wire together to a single wire, consider using Posi Tap, Posi Lock or other Posi products. Sure makes life a lot easier.


I had never heard of them until I added the Fuzeblock and Hyperlites to my RT and now I swear by them.



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  • 1 year later...

That's a great post for me as I am just about to fit the same kit to my RT! Thanks. I did wonder whether an easier access to the switched lead might not be found within the bundle of wires going to the heated seat (though do not know which colour). Any thoughts?

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Great job, nice post.




One comment: For those w/o esa, or who may go from esa to non-esa in the future, the location of the fuse block will interfere with any hand turned pre-load adjuster mounted in the bmw preferred location.

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Mitch -Nice install! I vote for the neatness of opening the connector to shrink wrap without cutting even though it takes a little care.


I've got an EB that replaced a Centech AP-1 on my bike so its running with a modified Centech Ap170 harness that has a 70A relay and heavy duty connections. Have mine set a little further back on the fender, though.


EB is a good source for a lot of high quality parts for those who are adding stuff to their bikes- including some good connectors though I prefer the versatility of weatherpacks that EB doesn't sell.


ARH- re another point to pick up a wire at the back- look at the photos and find the cube just to the left of the round diagnostic connector plug (near the rear brake reservoir in the photo). Inside that cube that opens up very easily is the starter relay. I pulled the trigger for mine off the higher voltage side of the starter relay coil- you can ID with a voltmeter. This point gives instant off with the ignition switch, not the delayed off that happens with the accessory outlet wire hookup.


Some folks have connected to a thin (green, IIRC) wire going to the diagnostic connector but there are reasons not to do that proposed by some.


The EB box (or the Centech AP-2) is a good choice because it allows easy install of a non-switched accessory outlet so you don't have to worry about riding 2 up with electric gear or you want to charge your battery through it without buying the expensive BMW charger meant to work with the stock ZFE-controlled outlets. I put a powerlet on my RT directly opposite the stock rear accessory outlet, mirrored on the other side but connected to my EB box.

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That is a very nice install, you took your time and it shows.

I think it looks much better when accessories are added and it doesn't look like your bike coughed up a wire ball.

I use vacuum or washer tubing as an insulator for wire that pulls some amps. It offers good protection and blends into the bike.


I see you have the best color BMW ever sprayed on a bike.

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I put a powerlet on my RT directly opposite the stock rear accessory outlet, mirrored on the other side but connected to my EB box.


That's a great idea I use the BMW charger in the accessory outlet but a power outage can throw a wrench it that.

The socket looks as it should and you won't have to worry about the ZFE shutting it off with a power loss.

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