I just saw a reply in my CP from a couple of days ago. It doesn't appear in the thread so I missed it. I understand you have a test light. That will get us started. I will picture the relay that my Damon uses. These are pretty common. If it clicked it would help make sure it is the correct one. You should have chassis battery voltage on one big terminal and coach battery voltage on the other one. It will be hard to tell the difference with a test light. One of the small terminals should be grounded and the other should have 12V when the aux. start button is pushed. This relay should close when the button is pushed and combine the batteries for power to the discharged battery. Remember you have to hold the button in. If you do not have power from the aux. start switch to the relay, after you determine which small terminal is ground, try hooking your test light clip to power. You can use either side of the relay for power. Carefully touch power to the small terminal of the relay that is not ground and see if it clicks closed. If it does, the problem is in the switching circuit. If there is power from the switch when pushed in, the relay is likely bad. There may be parallel circuitry that uses the same relay for a BIRD.
2016 Wildwood 28RLDS
2014 Tundra 1794 Platnum,"23" T-Bucket
2011 Harley Softail, 2010 Spyder RTS