For those of you who are planning on tinkering with the ECU, or any of the other troublesome critters behind the glove-box and kick-panel, etc.: First read everything completely - you will have a good idea of what to expect. These instructions are for a '92LS 400 (gen 1), and may or may not apply to other year models!
1. Open the glove-box (GB), and look carefully for five plastic "plugs"; I say carefully because these are felt covered and are cunningly camouflaged to blend in with the luxurious felt lining in the glove-box! There are three on the bottom and two on the roof of the GB, evenly spaced apart;
2. On my car ('92LS400), I used a small electronics type flat-blade screwdriver (2-3mm blade width) to carefully pry up (down if you are working the roof) the plugs. Set them aside where you can find them again (important);
3. Look at the left and right sides where the GB open door is supported by flat arms - if you look carefully, there are odd-shaped plastic caps on the ends preventing the flat arms from wandering off and allowing the GB door to flop around uselessly. Identified them?
4. Using the same small screwdriver, put the blade between one of the arms on the outside but on the inside of the plastic cap, and very gently pry it off - they should be pried off sideways - toward the driver's door for the support on the left and toward the passenger door for the one on the right. By way of explanation, the GB door has two small plastic pivots/dowels facing outward and the supporting arms slip onto these two dowels/pivots, and the caps simply slide onto the pivots to keep the arms in place. Sorry I cannot provide a better description, but if you work carefully and gently nothing should break. Got these two things off?
5. Move the two supporting arms off the pivots and get a wide thin, but hard plastic sheet to use as a wedge/prying tool ( I used two or three small flat bladed drywall applicator tools and risked damaging the dash - happily no damage resulted!) Explanation - you are going to pop out the GB liner which should now be free, except for the two supporting arms; Insert the thin plastic wedge into the space above the felt liner and the GB opening and gently pry the liner box out - it is one unit and you will have to work it, perhaps from right to left or left to right, but it is relatively easy to do; it may help to carefully use another small screwdriver at the top left and right corners because the dash material may have swollen and covered the edges. Once you have worked the liner loose, you will need to maneuver it around a bit because the right (passenger side) support has a spring retractor mechanism built into the liner and you cannot simply pull the thing straight out; you will also need to disconnect the lamp, so while maneouvering the liner, do this as well;
6. A cautionary note is in order here - the left GB supporting arm appears to be free-floating once the pivot stay is removed; I would suggest taking it out and putting it somewhere safe until you are actually replacing the liner. I simply left it in place expecting to hook it back up when I was done, and the ill-begotten offspring of unmarried parents disappeared, possibly into the bowels of the beast. I can assure you the air around turned several shades of blue, but that's another story! Just learn from my mistakes. Also, set the liner someplace it can't get sat on after you get distracted by your freely expressed opinions about Lexus engineers, technicians and their ilk for making it such a pain to get to things!
7. When the GB liner is out look for two 10mm bolts at the bottom right and bottom left - these were hidden by the lower part of the GB liner and must be removed.
8. Next remove the lower kick-panel; this was a RPITA (the "R" is for royal), but thanks to Freegard, I finally got if off! Look for three plastic fasteners going directly upwards - these are very close to the firewall and not easily dealt with; I thought they were metal and "screwed" around for awhile not getting anywhere (air turned blue again with vituperation toward certain engineers, and their ancestors who are probably very, very upset) - they are best dealt with using a "clip remover tool" some kind of gadget that slides under and allows levering/prying them out. Got the clips out?
9. Find some space at the top of the lower kick-panel on the right and left, where the panel abuts the one above it; once you have a good grip, pull it straight out toward you - this means parallel to the ground; there are/should be four spring loaded clips that hold the lower kick-panel in place once the plastic clips are removed. It may be a bit hard, since the clips don't readily pop out, but you will not break anything if you pull it straight back and have removed the plastic clips; you will still have to disconnect the courtesy lamp at the bottom of the kick-panel before it will come free so don't horse it yet! Got that out?
10. Look at the bottom of the middle panel - there should be four 10mm bolts (going upwards) securing this to the chassis/dash frame. Note also that there are two spring clips that also hold this panel in place. I think the two middle panel spring clips are really for positioning it correctly - i.e., to line up things. Remove the four bolts, and pull downward gently; wiggling may help, but it will come out. Again, you certainly don't want to horse things here because the ECU is mounted onto this panel and the ECU has a *@#!load of thin wires coming out of it and you don't want to dislocate any of these!
11. Put things back following the above process in reverse order and you are done! Whew, time for a well deserved beer break and figure how to get a replacement GB support arm!!!