Outer Limits 4x4 Board

I have a 2.8rx GQ that i did a 4.2td convertion on a while back.
When we did the convertion we had a auto electrition splice in the glow plug timer into the 2.8 computer thing in the drivers footwell. All was well untill the last week. Lent the car to a friend and got it back with no tail lights and no dash lights. When checking the fuses i found a heap of burnt wiring behind the fuse panel. Then today had a heap of smoke come out of the dash . Ended up burning most of the wiring harness behind the dash. What i am wondering is if any other harness can be used from any other engine type to plug in or how hard it will be to change the whole harness over to 4.2diesel. I know that i willhave change the dash cluster as well but how difficult to replace the whole harness? Cheers Jamie H

Harness is easy enough to remove. But the dash and air venting plumbing needs to be unbolted and pushed forward. Then disconnect all the wiring under bonnet. I found it easier to remove the brake booster, this allows everything to be transferred through the firewall holes. Disconnect the rear wiring from under the passenger seat. It should all come out in one go. I've just done this twice - one for my 4.2 diesel and one for EFI petty.