Why does my 1998 lincoln continental drain the battery, have flickering dash lights, fluctuating power steering assist, and disabled air shock pump continues to run even with switch in trunk off?

Battery drain caused by a short to ground (frame or body) somewhere. Most likely this short is intermittent, which makes the dash lights flicker, similarly the power steering assist. Most likely the trunk switch issue is the "short to ground" . Visually inspect carefully all wiring in near and by the switch, and Air Shock Pump. I like the new very bright Led flashlights for this kind of thing. You may also discover the short by observing the trunk electrical in the dark while the engine is running thus viabration causing the intermittent behavior. You may see flashes from the short (if you are lucky) Otherwise it will take a lot more inspection and checking. Good luck, hope it is the easier to find in the trunk.