The reserve lighting unit (RLU) is a neat piece of electronics designed to compensate for a burnt bulb by lighting the other filament at a lower intensity and giving an indication to the operator of a fault condition. This was incorporated into the early US GL1000's in anticipation of a legal requirement that never happened. The RLU was dropped in the 1978 and later models. Information on the RLU is sketchy at best. This is where having multiple resources helps fill in some of the gaps.
The Honda manual describes what to check for inputs and outputs to determine if replacement is needed
(38420-371-671, no longer available but $215.55 from mother Honda if it was.)
The Clymer manual mainly describes how to bypass a faulty RLU.
Randakks.com references Clymers bypass but recommends keeping it operational.
The Haynes manual doesn't mention the RLU, which isn't surprising as it is a UK publication and they don't have them.
The Cycleserv manual has some basic (block diagram) descriptions of how the RLU works, testing, and troubleshooting.
WOW! is all I can say. Thankyou so much for your time, I was getting real bummed.I hope I will be able to help someone on this sight that much.All I did was change the fender that was shot to a 79cb650 fender and clean up some wires that were bare in spots that had wires that looked like lamp cord solderd to them. they did not lead anywhere,prob some extra lights back in the day. thanks again Rob
I have been fighting with the "bag lady" for the last few weekends thinking that the PO had fouled the wiring so badly with all the extra lights and junk that I may never get it sorted out. All I can conclude, after chasing down every rabbit hole with a friend who is an electrical engineer is that the RLU is toasted. Thank you so much for this great discussion...really appreciate what you did here and many other places on the site. I am very grateful for your investment in our restorations.
Wayne
1976 GL1000 LTD #5117 "Bag Lady" is in Al’s (Dogboy) very capable hands!
