I used to have a similar problem (or same problem) on my 84 GL.
The light started to blink as soon as I turned on the ignition
switch. It is supposed to blink for a few seconds then stop. But
it would keep blinking for a while. It would turn off after a
minute sometimes a few minutes later.

The problem disappeared after I worked on my odometer. I had
to take the odometer off and put it back on a few rounds.
After fixing the odometer the blink problem was gone too.
It's of course not in the odometer. I guess it is in the circuit
inside the instrument cluster.

David

--- On Tue, 9/1/09, Ian Allan <ian.allan@BMTS.COM> wrote:

> I just got my daughters 84 on the road and have a pesky
> flashing
> coolant light. Coolant level is fine. Operating temp is
> fine but the
> light flashes. I attempted to loop the circuit at the
> bottle plug but
> that pesky light just keeps on flashing. Ideas?
>
>
>
> Ian Allan
>