[Richard]

That’s it!

But a few seconds with a voltmeter will tell you if you have a light problem or a merge relay problem.

Measure voltage on both terminals to ground. They will likely be different. Record the numbers.

Now, take a jumper from either of the terminals to the small post in the center. That activates the relay.

Measure the voltages again. If they approach one another compared to the previous measurements, then the relay is working. If the voltages don’t move, you need a new relay.

I am suggesting this test, because the annunciator(pilots, what you gonna do with them?) light is powered by the switch up front, it just tells you if the switch is made or not. It does not tell you if the relay is working.