Buzzer sounding in dash

[Rose Mary]

Hi group
Left Willits, CA today, heading N on 101 back to Oregon. About 60 some
miles into the drive a buzzer started sounding in the dash.
No lights, all gauges in the normal range. Not overheated....hmm
Checked all fluid levels before we left.

Pulled over in a safe place and did a walk around, everything fine.
When the radiator cools I'll recheck fluid level.

When I turn the key on without starting the engine the buzzer comes
on...not low air etc.

If the rad. level ok , any thing I should be forwarned about if I
drive on the Eureka, another 80 miles or so?

Bird is running fine....

Thanks
Rose Mary
82 FC 35
JP's White Bird
Heading N on 101
between willits and Eureka