Looks awful dry in there. However that chain is supposed to get lubed aint working. Is the shallow end of the pan in the front? Can you look in or stick something in the pan to see if there's oil there? Maybe it is supposed to splash or sling oil up from the pan.
My 84 Ford shop manual has a detailed write-up of the 1G alternators. Rear Terminal 40 & 60 amp. 8 Pages. Side Terminal 70 & 100 amp. 7 pages. I can scan and post the info if you are interested.
Continuous memory codes are generated while you are driving. They are stored in the KAM (Keep Alive Memory). When these are the only codes you get, you have an intermittent problem. As Beau stated, they can be reset by disconnecting the battery.
You should first clean-up any "hard codes" found by KOEO (Key On Engine Off) and KOER (Key On Engine Running) self tests.
Warm up the engine before the self tests.
KOEO: Runs self test and post fault codes or code 11 for no faults. Code 10, a Seperator, then posts memory codes. KOER: Posts a 4 indicating the ECU is for a 8cyl engine. Runs self tests and posts fault codes or code 11 for no faults.
When the cam changed the firing order it also changed the sequence of the intake valves opening. Your stock EEC is firing the injectors in the wrong sequence. The injector should fire when the intake valve close to it is open.
If your EEC has a Brown/White wire on pin 30 you're OK there. The 88 EVTM shows it wired. They may have made the change in 87 but the EVTM didn't catch-up untill 88.
In my internet searches, I have not been able to find an illuminated switch that would work for you. They all use the switched circuit (brown wire) as part of the light circuit. You want the light on when the brown wire is plus or minus (active or inactive). Not to say there isn't such a switch, I just can't find one.
You could use a common double pole switch to control the "Brown wire" and a light that's not part of the switch.
With the headlight switch off: The cluster LCDs should be on full brightness. Powered through the ignition switch in Accessory or Run, fuse 6 and the normally closed contacts of the Cluster Illumination Relay. The trunk release is also powered through Fuse 6. Does that work?
With the headlights on, the cluster LCD brightness is adjustable by the dimmer control.
Looks like the "Premium Sound Switch" turns on an additional amplifier to put it in "Boost Mode". In the EVTM it's called the "Amplifier Switch" I guess it's used if you want to rattle the neighbor's windows.
Trimmed the diagram down to just the Turbo Coupe part. Connector C286 is a gray 8 pin connector. "LH front fender apr0n, near voltage regulator." If you still have the 1G alternator with the external regulator.