1982 Kawasaki 750 LTD headlamp issue

Ok, so when I have the reserve lighting unit in my 1982 KZ750H plugged in, my headlamp warning light stays on, and my highbeam is very dim. When I bypass the RLU it seems to work okay. Ive tried 3 RLU's so I know its not the problem... any suggestions?

I'd remove the headlight from the housing, and use a multimeter to check the voltage at the three prong connector, also, look at the high/low switch for corrosion in the left handlebar switch pod.

The older Kawasaki's are starting to show solder joint failures, so if the soldered connections are looking Grey, or Grainy, they probably need reworking(re-soldering). If you have soldering questions, I've got a repair procedure, just ask.