Thought I would revisit this as we've been having a lot of posts or probable main relay problems recently. This is how to swap it, its not difficult. Worst bit is where the relay is located.
The new main relays from Honda have changed a fair bit, the part number is still the same 39400-S10-003
The internals are different as well
Tools requiredSmall socket wrench
10mm socket
Small extender bar
Torch (possibly)
Should take no longer than a few minutes
Pull off the fuse cover
Undo the 2x 10mm nuts holding the fuse board in
The main relay sits in behind the fust board, it makes life a little easier to move the board out the way a touch. Its held in with 1x 10mm nut at the top.
You may find it easier to remove the relay next to it, its only held in with one 10mm nut.
Refit in reverse, job done.
You can resolder the relay, however I've never had much joy getting these to last much longer than a year before they need doing again. Honda charge about £60 for a new one, I'm sure you could find a new relay from mitsuba elsewhere. You'll notice the rats nest of wires around my relay, that'll be the immobiliser wires.