Step by step removal of 2006 GL1800 trunk - 2005 Honda GL 1800 Gold Wing

Hi, Anonymous for this scenario you will need your service manual that has all fastener torque specs -fluid capacities and a wiring diagram on the back pages, parts fiche, and owners manual if you can not find the best tool you ever bought for your Honda, despair not, for a mere zero $0 you can download another one.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day.
https://www.goldwingfacts.com/threads/left-hand-controls-replacement.669697/
https://www.goldwingowners.com/threads/06-gl1800-right-handlebar-switch-assembly-replacement.126485/
https://www.manualslib.com/manual/1142922/Honda-Gl1800.html
https://www.partsfish.com/page/oem-parts-for-honda
https://www.manualslib.com/manual/805153/Honda-Goldwing-Gl1800.html

Follow page 109 of the manual at
http://www.awingaway.co.uk/GL1800-2010-NAVSYSTEM.pdf

Asuming you mean taillight/turnsignal, and not highmounted brake light:
1.open the trunk
2.Remove 4 wingnuts on trunk trim (there are two on each side)
You can do it by only removing 2 on one side, but it makes a nicer job,
3.Pull back the trunk "trim" the carpeted cardboard
4.Remove 2 wingnuts which hold the taillight assembly in place
Pull out the taillight assembly; you might want to remove (i.e. unattach or unplug) the wiring harness
5.Turn the particular bulb's socket (there's 5 back there: 2 tail, 1 back up, 1 side marker, 1 brake/turn) counterclockwise, and it removes from the assembly, holding the bulb.
6. Pull out bulb and replace.
6. Reverse steps to reassemble.

easy with a wrench from wingstuff.com, filter, and 4 quarts of oil. No need to remove any panels except right side chrome cover to add oil. Drain plug and filter are on the bottom front of the engine.

You need long reach spark plug spanner ,which should be in your tool kit .removal is easy ,But take care that you do not cross thread the spark plug when replacing them.this could be very exspensive so take great care .

all you have to do is inspect the old trunk door how it is attached to the hinges.

be careful on the tension bars that are lifting the trunk. once you released them, the trunk would just fall down.

there are two of these tension bars, they are like springs to help you lift the trunk and they are very tricky to remove and install
after you have done that then it just a matter of removing 2 bolts on each side of the hinge and remove the trunk.

if you have electrical accessories attached to the trunk such as solenoids or trunk cables, remove them first.

then do the reverse on installation.

you may want somebody helping you hold to the trunk before you remove the bolts. they are heavy.

tnx 4 using fixya,

drcool