It's quite possible the conversion harness has an issue but Brian's work is mint so I doubt it. Melting? No it all runs at the top of the engine then straight through the firewall. Still possible though. The gauge when working right sits really low which is odd. I've been meaning to swap in my SR5 cluster anyway so I'll start there.
"-1988 Red Hilux Standard frame, X-tra cab, locked F&R, 5.29's, 35" tires and a SAS. In Moab
"-1988, 1999 3.4L, Supercharged, 2.1" URD pulley, URD 7th injector, 2 1/2" Magnaflow exhaust, TO DO: lift, locker.
"Did you know the IFS was designed by Hitler himself to make the life of 4WD owners tough? Yeah, it's true, he saw a vision of the Devil and he told him to do it." -DaveInDenver