Any of you having trouble tracing intermittent dash light flickering? The charge, filter, and T-belt lights flickering on my 81 diesel finally traced to a fatigued wire at one of connectors on the charge lamp relay socket. The relay was fine. The wire was making and breaking intermittently. Bypassed the socket with individual connectors and long time mystery solved. The relay is obsolete and pricy on ebay, so check the connections too.

Worked for me. If you have a similar issue, maybe that's your fix.

 

Mine does it sometimes when the battery is at a high state of charge, It's an old Toyota thing, as soon as I use any electrical item it stops. I've seen old corollas can coronas do the same thing.