Auxiliary Fuse Block

Revised: 04/17/2007


I wanted to install a power port and other electrical accessories on my GL800, but before adding any accessories that require electrical power I though it would be wise to install an auxiliary fuse block. I want to thank fellow wingers on various bulletin boards for giving me tips on how to accomplish this project. My problem is that some times, what I read does not make since; I am a visual person, and I'm a little slow.

This is what I want to accomplish:

I want to install 2 Auxiliary Fuse Blocks.

I want one Auxiliary Fuse Block to have power when the ignition key is set to ON or ACCS.

I want the other Auxiliary Fuse Blocks to always have power.

The Relay:

The pins 86 and 85 are used to activate the relay's internal switch. Very little current is needed for these pins, and 18ga wire is adequate. First, I had to get an understanding of a relay switch and how it is wired.
The Radio Shock 30-amp relay has the following schematic. I interpreted the schematic as follows:


87 – connects to the M/C battery (positive)
85 – connects to the ground side on accessory terminal of the m/c fuse
86 – connects to the positive side on accessory terminal of the m/c fuse box
30 – connects to the 12V IN of the fuse block



NOTE: I looked at several relays and after comparing the instructions that come with them, I came to the conclusion that pins 30 and 87 are interchangeable and so are pins 86 and 85.


Advance Auto Parts 18ga wire   $2.79
Advance Auto Parts 12ga wire   $2.79
Radio Shack 30-amp automotive replay 275-226 $5.99
Advance Auto Parts Buss 6 circuit 30-amp fuse block   $7.88
Advance Auto Parts Assorted crimp-on connectors   $8.99
Auto Zone Junction Block (Barrier Strip) 85685 $3.49

The Auxiliary Fuse Bocks:

The first Auxiliary Fuse Block will work of the motorcycle’s ignition switch and will go through a relay, to help prevent voltage spikes. Some (not all) electrical devices will be wired straight to this Auxiliary Fuse Block, but others will have their own relay for added protection.

The second Auxiliary Fuse Block will be wire to the battery and is always HOT. This Auxiliary Fuse Block will be used to power additional relays.


I decided on the Buss 6 circuit 30-amp fuse block because it has a low profile and it uses ATC fuses. The fuse block is rather small and, in the future, I can add another fuse box and not worry about space.

Note: Regardless of what wire gauge size you use the weakest link should always be the fuse.

The Wire:

Based on the wire chart at ( ) I decided that I would only need to use four sizes of wire 18ga, 16ga, 14ga and 12ga. These four sizes, of wire, should be more than adequate for any electrical accessories added to my GL1800. I also used crimp-on connectors.

NOTE: You will need very little wire for this project. The leftover wire can be used on future accessories.

Crimp-on Connectors are color-coded:

Color of Connector
Size of Wire
Red R 18-20-22 gauge
Blue B 14-16 gauge
Yellow Y 10-12 gauge

The Master Ground Block:

I want to make sure that all the electrical accessories have a good ground, so I figured that the best solution would be to install a Master Ground Block. Radio Shack, Auto Zone, and Pep Boys Auto all call them by another name like Junction Blocks or Barrier Strips.

I bought two different types of Junction Block (Barrier Strip), one from Radios Shack (Cat. No. 274-670) and the other from Auto Zone (Cat. No. 85685) Both Junction Block (Barrier Strip have to be jumped to make them into a Master Ground Block.

Auto Zone Cat. 86685 h i

My preference of the two was the Junction Block (Barrier Strip) from Auto Zone.

The Auxiliary Fuse Blocks:

12ga wire for the Master Ground Block
87 – 14ga wire -------- 14ga can handle almost every thing. LED lights can use much thinner wire.
85 – 20ga wire -------- You can use a thinner gauge wire. This only used to trigger the relay
86 – 20ga wire -------- You can use a thinner gauge wire. This only used to trigger the relay
30 – 14ga wire -------- 14ga can handle almost every thing. LED lights can use much thinner wire.

Here are several options to consider:

Option 1


Option 2


Option 3




  1. Remove the seat. I choose to install the relay and the Master Ground Block under the seat.
  2. Removed the bike's left side cover of the bike to expose the battery and fuse box.
  3. Remove the fuse box cover.
  4. Open the left saddle bag.
  5. Under the seat at the M/C crossbar secure the Master Ground Block with nylon tie-straps.
  6. Place the Auxiliary Fuse Block "A" in the left saddle bag. I used 3M double sided tape to stick the fuse block to the rear of the compartment.


NOTE: Originally I installed the Auxiliary Fuse Block on the metal bracket that secures the battery, but the M/C side cover would not seat correctly.



  1. Place Auxiliary Fuse Block "B" to the left of the M/C Fuse Box and secure with nylon tie-straps.


  1. Reinstall the fuse box cover.
  2. Close the left saddle bag.
  3. Reinstall the left side cover.
  4. Reinstall the seat.

Additional Comments:

Now that I finished installing the Auxiliary Fuse Blocks I'm ready to start installing electrical devises.