Thanks Satch. The voltage drop at that outlet is still occurring. I have those covers off and the carpet back, finding those bolts in place intact. I need to find the actual ground multi-tap because I suspect it to be disconnected.

Wires to the stereo were butchered, the oem stereo unit was just bolted back into place. It looks like a quick job to sell the car without an empty stereo hole in the dash.

An less interesting alternative would be to tap the ground from the lighter and re-ground that to those console bolts you mentioned. If all the individual grounds are still attached to the JC-03 it might work. If they are not, then it will merely mask the problem.

i believe that is what he meant, to add a new ground.

Yes, I see. If the other ground wires from those systems are still attached to the multi point ground terminal, grounding any of them would likely solve the problem.

My hesitation with this is that if the ground point has been removed/cut/hacked off (like the stereo wiring in the same area) , perhaps the other systems that sharing that ground are still inadequately grounded.

Those systems are:
Glove box light switch
Electronic control switch (mirrors in console)
Warning lights and Clock

Obviously, the lighter pulls the majority of the current compared to the other systems. All those systems work, but then so did the lighter.

4 Year Update: Problem Solved
 

IDK if anyone is still on this forum that knows me, but here is an update: After chasing grounds, and failing to solve the problem, I stored the car for 'later'. I sold the 90 Vert. Bought an SL55 AMG and pretty much forgot about RX7's. Then, this summer, I pulled the 10th Anni out of storage and started in. The voltage drop led to drivability problems, so I dived in to finally run it into the ground.

I looped a wire around from the battery to the interior fuse panel. The issues disappeared. Seems the voltage drop problem wasn't in the grounds, it was in the supply line to the interior fuse panel! So I methodically checked each connection, including the mythical crimp somewhere in the main positive cable. I de-wrapped the main harness and found the crimp, but is was clean, shiny with no corrosion and no measured resistance across the connection.

Swing and a miss!:confused:

One quick look at the FSM ( I have a paper copy too) solved the problem. All the voltages that are dropping or causing the drop are *SWITCHED* circuits. The current goes directly through the IGNITION SWITCH!

A brand new ignition switch has solved the problem completely.