Hi George,

Although perhaps not the most common failure mode, a faulty Bulb Failure Warning Sensor is the likely reason for the condition you see. Simply reach under your dash, feel for the "can" and unplug it. Try again. Of course the monitored lighting will not operate, but if the warning lamp is no longer lighted, you can rule out a pinched wire or fault in the cluster.

With a 1980 so new to you, there's also a general possibility it has had some monkey business in its repair history, so unless you know its life history, keep the technician-induced causes in mind while you troubleshoot. Otherwise, swapping in a new or good used "relay" will fix you right up.

If you're into details, open it up. The coils you see inside will have tiny glass reed switches inside them. If one is cracked (likely if someone else opened it before you) that would explain why it is lighting the warning lamp. Any one of them could do it.

P.S. One of the technician-induced scenarios could be, I might guess, that a newer, post-1985 style sensor was tried as a replacement. Yours should be black and p/n 1362278.
--
Art Benstein near Baltimore

"The more people I meet, the more I like my dog"