Ash's 2004 Patrol GU III TD42ti

[Cremulator]

EGT, boost and dual voltage gauge install

So this had been on my list of things to do since I bought the car over 12 months ago but it turned into a more challenging problem to solve that I had originally anticipated.
The car already had a 3 inch Manta exhaust, but for some reason the aftermarket dump pipe didn't have a bung for the EGT probe.
I looked into getting a bung welded on, but as the dump pipe was cast it has to be done further down the exhaust. I decided to replace the dump pipe and found another Manta 3 inch dump pipe on Gumtree that was brand new and got that for a good price.
I had a go at removing the old one, cracked 8 out of the 9 nuts, then started rounding the head on the last one so thought I'd better give it to my mechanic to remove. Lucky I did as the gaskets needed replacing, which I hadn't sourced.
This is the old one that was removed:
this is what the new one looks like, identical but with a cast bung:

Cabling runs along the firewall using some of the existing clips and into the cabin through the drivers side.
I decided to mount a couple fuse boxes in the left side of the driver's footwell. Cardboard template, translated to some 40mm x 3mm aluminium flat bar using two factory mount points.
The idea was to have one fuse block powered off the ignition ON wire and the other powered from the headlight illumination wire on the steering column.
The ingnition ON worked well but my idea of running the gauge illumination to the headlight wire and earthing it to the dash light dimmer didn't dim the gauges when I dimmed the dash lights (I'm learning). I then worked out I had to connect the illumination wires from the gauge to the dimmer switch, but not to the earth wire, to the two wires that had a positive voltage reading.
I connected the grey wire from the gauge (to park light positive) to the blue wire on the factory dimmer and the brown wire from the gauge (to dash light negative) to the pink on the dimmer. This dimmed the gauges properly with the dash lights.
The dual gauge pod (which I purchased colour coded from Patrolapart) fitted snugly and easily and looks great, but the grab handle sat out a bit as there is no plastic ribbing on the back of the A-pillar like there is on the factory one. I swapped the spacer with one from a child seat anchor point and that resolved the problem. All looks nice, neat and functional.