o.k. It looks like this analysis may be a waste of time, but here it is anyway. Looking at how the pilot indicators work, the text on the front: “PILOT FAILURE INDICATES SIGNAL FAILURE OPPOSITE LEVER POSITION”, and the two bulbs are labeled Front, and Rear. Using Johns picture in the left turn position, I have added some colorful lines. It looks like the pilot bulbs contact is connected to where one of the the switch contact is at 7 o’clock for the front and 5 o’clock for the rear. I’m making a couple assumptions about the pilot bulbs. The pilot bulbs operate in both directions meaning that their ground is switched depending on the direction selected. The pilot bulbs must have much greater resistance than the signal bulbs(or would it be the other way around?). For the left turn setting we can see, indicated by the pink dashed line, the left front and rear signal bulbs are connected. What is not so obvious is that the front pilot is getting power to it’s contact, and the case is going to ground through the right front signal bulb. The rear pilot is getting power to it’s case and is grounded from the contact through the right rear signal bulb. Both pilots are illuminated, using the opposite side signal bulbs as ground. If one of the opposite side bulbs burns open, the pilot will fail to illuminate. The opposite side does not illuminate because of the proportion of current going through it. Hey that’s pretty neat, does that make sense, or am I off my rocker? The next thing to look at is what are the bulbs rated at? Pilot vs signal?
