Study the schematics in the FSM (pages 8W-10-23, 8W-31-6, and 8W-31-7 of 2001 FSM if you have it - may or may not be similar page numbers of other year FSM's - but keep in mind that 2001 was a transition year, and some circuits changed from 2000 to 2001, and then again from 2001 to 2002 - I suspect this circuit is the same, other than the TCM being in the same box as the PCM starting in 2002 - without looking in each FSM 2000 thru 2002, I can't say for sure).
Fuse Q feeds the TCM and the contacts of the transmission control relay, which feeds the transmission solenoid pressure switch assembly. Something in that circuit is shorting out: A wire, the TCM (probably not the problem since you tried a 2nd one), or the solenoid pressure switch assembly. Trace wires - if no short, likely the solenoid pressure switch assembly.
'98 LXi - Later Concorde gages (black w/ chrome rings)/'99 LX - LHS gages (white) - HIR bulbs