I found the file I sent you, and it is the correct one.
I think some clarification is needed on the two methods. Ron already covered much of it earlier in this thread.
The "clean" method requires pulling the dash to replace the instrument panel harness with one from an ATC vehicle. The extra work in that method is in removing the entire dashboard. As Ron pointed out, the reason to go to all the trouble is that the ATC harnesses (separate from the instrument panel harnesses) will plug into the instrument panel harness that came from an ATC vehicle - no splicing, everything will be factory.
The "splice" method adds the ATC harnesses but uses the existing instrument panel harness made for MTC. You don't have to remove the dash, but you do have to do some re-wiring to make up for the differences in the two versions (MTC and ATC) of the instrument panel harnesses. That is what the document I sent you tells you how to do.
As far as the sun sensor, I believe the MTC instrument panel harness has the connector on it already, it's just not hooked up (because some vehicles with MTC and certain accessories also required the sun sensor). After making all the wiring changes in the instructions, and installing the sun sensor, it should work. You'll see an oval outline on the top surface of the forward dash trim panel for the sun sensor to poke through from underneath once you get the sensor installed. Just drill through that oval and use a Dremel or jeweler's files to shape the hole exactly to the outline, and it will look factory after the trim panel is laid back down. If I'm right about the sun sensor connector, you should find it in the cavity where the sun sensor goes - unused until now.
The fact that the instructions list the sun sensor in "Parts Needed", but don't mention it in the wiring supports my thinking that the connector is already built into the MTC instrument panel harness - you just have to plug it in. You might have to find/buy some screws to mount the sensor - easiest if you got the sensor with the screws.
(Ron - I emailed you the instructions a few minutes ago.)
'98 LXi - Later Concorde gages (black w/ chrome rings)/'99 LX - LHS gages (white) - HIR bulbs