TO REPLACE BULBS
Just unscrew the lamps out of the faceplate and replace.
TROUBLESHOOTING PROCEDURE FOR TIMING LIGHT.
If unit does not work at all:
1. Check battery orientation.
2. Replace batteries.
3. Check buzzer operation.
4. Check circuit connections for electrical contact and shorts.
If any one light is lit:
1. Make sure the three probes are not making electrical contact.
2. Replace light bulb.