The coolant temperature light doesn’t come on when ignition is on and in the “bulb test” mode. Is there a procedure to check the system? The bulb is OK. The Alternator and Choke lights both come on properly.
I would think you could simply take the Green wire where it connects to the temperature switch and ground it directly to the side of the block. This should illuminate the light bulb.
Coolant Temperature Light Switch Wiring Diagram