Not had it happen on TR7 but on my Integra the ignition light would come on often even though voltage reading was good and never had a problem with battery. There was a vampire drain in the system at .3 amps which meant when I left the car for three or four days the battery would be flat. I had sprayed the ignition switch with graphite and it was conducting a current when the switch was off (and presumably interfering with the ignition light balance circuitry). I flushed out the graphite in the ignition switch with silicone spray and the vampire drain stopped and the ignition light didn't come on. I would spray the ignition switch with silicone working it back and forth and see if that fixes the problem. Can't hurt and is probably something that should be done anyway.
- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 2013 Volt - Yellow TCT