So my '77 R75/7 is getting rebuilt from the bottom up. Needed a new wiring harness due to condition of original and many wires were bypassed or spliced or just not there. It was a mess. I watched several videos from Brook on the best way to do it and and everything looked great after I double checked all connections. One thing I noticed is that my left handle bar control only has 2 switches, one for horn and the other for hi-low beam. It doesn't have the 3rd witch which I guess turns the lights on/off??? MAX BMW shows this as a yellow switch. Anyway, once all connections were made, I performed a functional test which Brook performed in his video. I test in Park mode and then full ON.
My observations as follows:
In Park mode, both the parking light and headlight come on as well as tail light. I don't believe headlight is supposed to come on, only parking light.
In full ON, no headlight, high or low beam. All other tests worked in the full ON mode, horn, dash lights, brake light and turn signals.
Attached is a schematic which came with the harness. The items with the X are the items not on this bike. Any suggestions to get the lights on when in full ON mode versus Parking mode? Because I don't have the third switch, there is an open terminal on the head light relay (86) and one less gray wire going to 58U on connection board. These items are all shown on the attached schematic!
Any /7 Airhead would be a mid-1970's model which came under later DOT rulings. Specifically, the "headlamp ON 24/7" ruling. Your schematic may be more generic, or for bikes from other nations which were not concerned with US DOT laws.Â
A USA version /7 would also have a relay to turn OFF the headlamp while the electric starter was engaged.Â
Occasionally you can find a European handlebar switch and return the older "headlamp OFF/ON" function back to the bike.Â
The parking light function is not needed at all in the USA. Some well-lit European cities had drivers using the parking light (in place of headlamps) to reduce light pollution. On English bikes with low-output alternators, it could be used as a method to charge up a doggy battery. But that was never an issue on the 12V Airheads.
New DOT rulings every model year were changing motorcycles forever....
Exhaust system cross-overs to quieten the exhaust note.
Side stands that could not remain down.
Leaner fuel mixtures (which eventually forced liquid cooling).
LH shift on all motorcycles.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
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