Hey, it seems silly and I feel like a fool for not keeping better tabs on this, but I was replacing what I presume is a fuse on top of the engine of my V12 XJS (1988), and I marked the wires... However, I forgot to mark where they go on the fuse and have forgotten what my markings meant. I thought I'd taken a "before" picture but can't seem to fid that either. I'd rather play it safe than sorry and figured I'd come here for help as I'm not really finding what I want on YouTube.

It has these four wires that attach to this fuse and a fifth one that I assume goes someplace within this 'box'. Any help with my blunder would be appreciated!

 

That's not a fuse. The thing in your hand is the ignition amplifier. It should be screwed into its box, ideally with some thermal paste to keep it from overheating. I don't seem to have any pictures from when I rebuilt mine, let me see if I can find a diagram.

There's a diagram and photo in this thread: https://forums.jag-lovers.com/t/help...ifier/383994/4

 

That is such a huge help thank you!

 

The amplifier is a General Motors 4 pin HEI system. Used on millions of GM vehicles from 1973 into the 80's. The V12 pushes the system hard, so ideally use only a genuine GM part. It's Delco D1906. The originals were made in Singapore, not sure where they are made now.

I've had plenty of aftermarket part not work out of the box and a GM replacement fixed the problem; so beware of any aftermarket parts if you have ignition problems.

 

This is what I have from many years ago, hence mt scribble in places.

There is a snap, somewhere, of the module inside the amp, thanks to Greg, who is on holiday with the XJS somewhere up north, so cannot be asked, but I will keep looking and post back when I find it.

Meantime, drink beer, solves all Jag problems.