I'm have a issue with installing a Harley Garage Door Transmitter on my 2000 Heritage Springer. First let me say I'm sure it isn't in the receiver as I have a opener on my Roadglide that works fine with the receiver. Its all wired up and programed and will only work if I run a ground to the yellow wire. There's power to the yellow unless I run the test light for the Batt. ground to the yellow wire. Then everything works fine. The way I found that out was with the test light testing for power while switching the high low switch. It also has a day maker headlight bulb.
Just unplug the Daymaker and see if it works.
Sounds like running a 1k ohm resistor from the yellow wire to ground would solve the problem.