Re: Wes's Maroon 1947 Custom Super Clipper

Posted by HH56 On 2020/7/19 14:20:56

The contacts in the flasher operate both the signal lights and indicator lights at the same time. The signal bulb total resistance needs to be a specific value to make the thermal type flashers work properly so that is probably the reason the indicator bulbs are on a separate output and not in parallel with the signal bulbs -- plus some cars only have one indicator light.

In this circuit, both indicator lamps are powered together from the P output but by having them connect to opposite sides, when one side is active the indicator light for that side can get its ground by going thru the filament(s) in the turn signal bulbs on the other side. If the indicator light was connected to the turn signal wires on the same side both wires to the indicator light would be at the same potential at the same time so the bulb would not light. In a single bulb indicator system the bulb would just have a regular ground.

Not sure why the resistors are on the indicator bulbs but cutting the briteness or heat generated near the plastic lenses in the dash openings might be one reason.