Outer Limits 4x4 Board

Hi all,
Today a relay located below the brake naster cylinder on the inner guard would click very fast when the ignition was turned on for about 15 sec. then stop, or if the engine was warm, when the engine kicked over.
I've sprayed it with WD-40 and it still does it, I tried using the aux batt. as well as the main. and it still clicked really fast, gave it a little tap, but nothing worked.
What I was wondering was, is it the glow plug relay located here? what else can I do to fix it? are they servicable? is this fast clicking bad for the glow plugs or the cuircut, will it still crank when cold if i glow it a couple of times? and any other info, where to look etc, would be great.
Also the alternator was recondition about 6 months ago.
Cheers.

if the connections are all clean try swaping the relay with another one the same like a horn relay or something to see if there is any difference

You have a dry joint somewhere - a dirty connection with a high resistance.

The voltage to the coil of the clicking relay is dropping while the glow plugs are on, or while cranking. I don't know what the clicking relay is, but it's not happy when your battery is under load.

Remove and clean all connections on both battery terminals, and also disassemble and clean all connections on any negative wires connected between battery, chassis and engine block.

See what happens then.