Yes, the new tail light has a quirk (OK, a design defect) in that it puts out about 8 volts on the brake light circuit when the tail light is on (all the time the ign. is on). This will cause various problems with any additional tail lights on the bike as well as defeat the brake light sensor on a cruise control (the CC won't engage with the new tail light in place).
To correct this, buy a diode and place it in- line with the brake light wire of the new tail light. Almost any diode will work but I recommend using one of the 3 amp types available at Radio Shack- they sell both 1N5402 and 1N5404 in the stores and either one will do. Diodes have a direction (they are a one- way valve for current) so they must be installed in the right direction as well as the right place in the circuit: install the diode with the band marking facing the tail light, and install it in the tail light harness itself (it must be installed 'behind' everything else in the circuit to work). Installing it backwards or in the wrong place (but in the right, brake light circuit!) will not hurt anything including the diode, it will simply not work. The best way to install it is to cut the brake light wire, solder the diode in series (in- line) in that circuit, and then use some shrink tubing to cover the exposed wires (it is easiest to cover the diode too while doing this).
If anyone needs more help with this I can snap a couple of photos of the basic idea.
Brian
I finally ordered the Admore kit for my E55 after watching your video last week. I ordered the new plug and play harness that goes inline with the factory harness. Did you have any issues with the new Tail light and the E55 working together? I thought I read a while back there was some issue when adding additional brake lights.