#1 checked bulb defective
#2 replaced bulb new bulb, didn't work
#3 removed switch broke it getting it out.
#4 called you ordered a new switch. Installed new switch. Didn't work
#5 Measured voltage ay light socket. Correct voltage
#6 Examined lamp socket. Found the base contact almost flattened. Why????????
#7 Adjusted base pin to make contact with the bulb. All is well. Curious why after many years the thing quit.