I know that this thread is olddddddddddddddddd. But I have something to add now and thought it may help someone dealing with what I was dealing with just a short while ago.......
I had the same setup with a remote for my garage door opener and had it hooked to the high beam on my bike. I hit the high beam for a second and the door lifts open.
What I did experience once in a while is that the door would not open (or close sometimes). I tried another door opener on the circuit and also saw the same thing.
I troubleshot and what I found was that my high beam circuit was only supplying 11.4v to the door opener. Probably just intermittently would be high enough to work, and at sometimes low enough to not.
I was going to do the headlight relay mod to get the full 12v to the lighting, and hence, the full 12v needed for my door opener.
What I did instead to avoid all the added work, was to install this $12.99 voltage step-up converter;
https://www.amazon.com/gp/product/B0759Y6WWW/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
I plugged the module (it's very small and fit in the tight space behind the left scoop and in the same area as the stock coils sit) into where I had the mini door opener. I have COP's, so that area has more room in there now anyway. Then I fed the door opener with the voltage coming out of this module. All works again and no intermittent operation. Now I get 12.2 volts to the opener when I put on the high beam.
This module takes my 11.4 volts from the high beam and increased it to 12.2 volts for use on the door opener.
Just thought I'd throw this suggestion out there for anyone wanting a bit more voltage to run some device on a lower voltage circuit.
For me anyway, it was hard to beat a $12.99 fix for this issue that I was having.
Vinnie