1981 ZX, it has the warning/check display in the center of the dash. When I first start the car I get the green "OK" but after a second or two the display shows the red warning. If I hit the check button, it displays either "tail" or "stop" as in lights. Both the tail lights and brake lights and blinkers work just fine but I still get the warning. Does anyone know what might cause this?

Check one more time. There might be a tail light bulb out that you did not notice earlier.

Try the following link over on zcar.com:

http://www.zcar.com/forums/read.php?f=1&i=590404&t=590348#reply_590404

Wayne Monteath had a few posts regarding this problem.

My zxt also has the same issue.

Earlsfork