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Another Headlight question


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Does any one know what year BMW did away with the headlight switch on the Airheads? I just got a 75 R90s & it doesn`t have a switch . I guess they thought they`d "help us out: & make sure we had our headlights on! Ain't Government great? Secondly what type of interrupter did they use to shut down the headlight when the motor was cranked?

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Am not sure about '75 models, but in slightly later year airheads, the starter relay has an integral "load shed" circuit that causes the headlight to momentarily drop out to reduce cranking amperage while starter is cranking. I think that's true for the '75s. It's the silver relay in the headlite clamshell. I can't easily find the part #, but I think there's only 2 relays in there. The other is the turn signal flasher. I think those starter relays are all the same for many years. Check with Bob's BMW.


In some states, govt. requires headlites on all times when moving. I was recently pulled over in TN for running without headlite. I had on lots of protective riding gear, it was sunny, and I about roasted while he checked out my insurance, etc. I think it was an instructional stop for a younger officer with him.


Get urself a "euro switch" (about $100); replaces left hand control (dimmer, lite on/off). It's a stock item at places like Bob's BMW. Make sure u get one for older airheads with electrics in the clamshell. Same switch for later models (monoshock) with electrics under tank have plug-in connectors, rather than bare wires. Installation is pretty easy. Good opportunity to prowl around inside the clamshell and clean/dielectric grease to contacts anyway. Many of ur electric problems on ur bike will originate inside the clamshell.


Euro switch is also great for reducing load on ur electrical system, such as in idling traffic, when ur alternator isn't putting out much.


Hope this helped.



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too old to care

My old 74 R90S had the headlight switch as part of the key. First turn bike would run, second turn bike kept running and headlight on.


I do not think a handlebar switch will work on your bike if it has the same switches as the 74. Both the turn signal switch and start button are round with levers on them to signal a turn or kill the engine. My 78 R100RS has the next generation switches which are completely different.


On my 74 R90S the key switch went bad and I replaced it, cost was about $100 and it also had the light function built in.


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