Il is the generic acronym for Check engine, check oil & check water, etc, lights. Otherwise known as Idiot Lights, LOL, but I guess indicator lamp works too.
Last time I checked, new tubes were still available from Radio Shack by mail order and there were tons of used, tested and guaranteed ones going pretty cheap on Ebay back in 2001. I remember the term VTVM but I have forgotten the exact wording (V Tube Volt Meter?). The VTVM was my fathers (passed away in 1984). I still have a huge cache of his old WW II surplus ham radio gear, including a heathkit tube model oscilloscope and my older brothers hand made 2 KW transmitter. I managed to hang on to about 200 tubes from back then too, along with a tube tester, but it needs a little work. Another round to it project. An engineer friend of mine has a working tube tester here in Houston.
Getting back to Jeeps, John Lang from this group emailed me the manual I am quoting from, last week. He also clued me into this fantastic group here last week. THanks John!!!
It is on page 86 under system diagnosis for the 1987-89 Renix models. See the Bold section called "KAM" halfway down the first column. Stands for Keep Alive Memory (KAM), so apparently the ECU has non-volatile rewritable memory after all, even though none of the other manuals ever mention it. You are correct that it does not store trouble codes, but it says it stores high and low failure values if they existed for more than 2 seconds. The manual John sent me looks to be more complete on the Renix ECU details than the ones you have posted on
http://autos.groups.yahoo.com/group/RENIXPower/files/
and it is more complete than the FSM version I just bought and just received 3 days ago (Jeep Renaul Component Service Manual, titled "Multi-Point Fuel Injection (MPI) Systems"#8989 010 547, INJ. MPI USA/Canada Edition, Revised January, 1987, 90 pages but half of it covers the 2.5 liter engine version, Copyright 1987, American Motors Corporation and Jeep Corporation, Cherokee/Wagoneer/Comache/Medaliaon).
I just uploaded the pdf of the John Lang manual I was quoting above to your Jeep group site:
http://autos.groups.yahoo.com/group/RENIXPower/files/
Time for a nap here, later....
Mike McGinness
South Houston, TX