The left side headlight does not work on my father's 1956 Olds 98.This just started yesterday.The guy whom does work on his classic cars can't even find what is wrong.I did the simple things,the plug in for the headlight has no corrosion and is clean.Did work for a little bit after I wiggled on the plug in.I noticed some mouse droppings on the floor where it is parked.I am figuring out a mouse somehow got inside and chewed on one of wires or it is a broken wire near the plug in.What could it be?I am done messing with it since I am not good with electrical on cars.

 

Not to sound too basic or such, did you swap bulbs to rule that out?

 

See if one of the wires from the socket goes to a place on the body - clean the connection to make good ground.
Also check the dimmer switch for a loose [or wet] connection.

 

It was not the bulb.It was the plug in,broken wire finding it tonight.Works fine now.

 

Great - time to cruise!