Lower bay area below the radio assembly

Any pointers for removing the lower bay area below the radio assembly in the SCL? Hunting for the ISO wiring harness to install an aftermarket radio.

TIA

There won't be an ISO wiring harness!
There will be one or more Toyota specific connectors and if you want ISO you can go to a car stereo place and buy adapter leads made by Aerpro that will plug into the Toyota connectors and have ISO on the other end.
ISO is not a world standard, it is common I believe among vehicles of European manufacture but everyone else uses their own connectors. The Aerpro range of adapter leads seems to cover everything you could imagine and their pricing is good, the result is far better and easier than cutting and splicing wires.

Yes. Those Toyota specific connectors are what I'm after. I believe I have the adapter leads ready for them. I just need to open up the area below the radio I believe to get to them.

Let us know what model adapters you end up buying, as this would be a great reference for others going forward.

Here's a far as I could get on Aerpro's site:

https://aerpro.com/vehicles/toyota/toyota-hiace-1989-2004#-

I'd have expected the connectors to be in the same area as the radio, likely to the right hand side. To get below the radio, can't you just remove the radio? It's usually just four or so screws once you get the dash panel out which is again usually only a few screws, look for the one(s) hidden behind the air vents at the top though!

Here's a video showing how to get the dash panel out.