<VV>Engine overheat warning buzzer ?

[Warner Butler]

New-boy, just joined today.
1965 Corsa Coupe, 4-speed, 140.  Setting the scene:  had to change the 
speedometer, so that was a dash remove/replace.  Then in 
trouble-shooting a starter problem, found that the ring gear was 
shredded in several places, so that was an engine/drive train 
remove/replace.  Now . . . .  the problem is a buzzing noise(ref. page 
12-10 1965 Corvair Shop Manual) in the center top of the dash(by the 
cylinder temp. guage) whenever I connect the negative battery cable. 
 The noise is present with ignition on or off and with the engine 
running or not!?!  I removed the dash again to check for pinched wires 
or no ground, etc.  During re-installation after I hooked up the dash 
cable bundle I connected the battery and no buzz!  After installing all 
screws, grounding strap, etc. the buzzing is back whenever I connect the 
battery.  It appears(?) as though the cylinder temp. needle is 
functioning ok - it was about 200 degrees(I didn't let the engine run 
long enough for it to rise).
Help!!  Thanks