I have several, 60 plus year old, turn signal switches, that look "OK", but I have no idea if they function properly.Is there a way to bench test them?
Thanks
John

John there is really no good way to test them out outside of a VOM.  The VOM will check continuity but will not show if the internals can carry current. 

I'm going to assume the leads are known.  Two leads, the flasher input and the brake input powered with 12V (one at a time) will show the continuity of the contacts with a test lamp.  The brake input, with the switch in natural, will have continuity with the two brake/turn for the rear.  Moving the switch to the left/right position will open one of them and maintain continuity with the other.  The flasher input will show continuity for the front turn one at a time with the switch in the left/right position (no continuity with any lead in the neutral position) in addition to the corresponding rear brake/turn.

To check the load carrying capability of the switch make a few test lights.  Parallel three lamps for each of the rear brake/turn leads and a two lamp for the front turn.  Hook them up to the respective outputs from the switch.  Apply 12V to the brake input, both rear sets should light up, operate the turn lever and see that they go out and turn on as expected.  The fronts should remain out.  Apply 12V to the flasher input.  No lamps should be lit, operate the switch and see that the appropriate lamps turn on.  Five seconds in each test should show the switch is good.

If you are going to run LEDs you need to do the test with them vice incandescent lamps. Dirt and cross contamination will make them do weird things.....

Thanks Bill.........That's a lot to digest! I'll give it a try.
John

I've always debugged the switch while it was still in the vehicle.  I would just plug it in under the dash and run it through the diagnostics.

Thanks Gary!