Author Topic: Fix It - I don't know, but if you have headlight problem on KAWA, this may help  (Read 821 times)

Offline PAULRIDES

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Found an explanation on a FORUM  http://www.ex-500.com/  that I use frequently as to how the Interlock between start up and headlight works. A guy took the trouble to sketch out his version of what is in the Junction Box (looks like a good analysis to me). It explains how the Engine Start and Headlight Power are interlocked at start up by a HEADLIGHT RELAY abd LOGIC in the JUNCTION BOX that controls the power to HEADLIGHT RELAY coil. It would help if I could put the schematic on here, but here is a link to the web site.  

http://www.ex-500.com/index.php/topic,19182.0.html
 

Kind of interesting -- Maybe good info for someone some day  

There is a set of Relay Contacts on the Headlight Relay in series with the 12v that comes thru the Ignition switch and a fuse to the headlight. These contacts are initially open and the battery 12v does not reach the Headlight Bulb when the Ignition Switch is turned on. Of course the 12v at that time (before engine start) is from the battery and later from the Stator/Regulator/Rectifier.  Those open contacts on the HEADLIGHT RELAY keep the power (12v) from the headlight itself and the bulb is not lit.  

When the engime starts and the alternator produces a output Sine Wave. One leg of the alternator Sine Wave is fed to a diode and results in a half wave unfiltered DC voltage that is connected to the HEADLIGHT RELAY coil. This causes the open contacts to close and then the 12v (actually, closer to 14.0V from the Rectifier Regulator Battery) gets to the Headlight Bulb. The light then lights.  

That same voltage at the headlight is routed back thru another Diode to the same HEADLIGHT RELAY coil and holds the relay coil energized even if the engine stops running. SO, the headlight stays on from the 12v thru the Ignition Switch, Fuses, and Closed Contacts on the HEADLIGHT RELAY even if the engine stops running as long as the Ignition Switch is not turned OFF.

EX: Like if you kill the engine with the Kill Switch or have kickstand down and release clutch which would kill the engine - in other words, anything that kills the engine, BUT LEAVES THE IGNITION SWITCH ON will resiult in the Headlight staying on.

ALWAYS WONDERED how that worked.        

« Last Edit: December 16, 2012, 10:44:20 pm by PAULRIDES »
Ride Country Roads - a lot. :-)

Offline Curtie223

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Offline PAULRIDES

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I posted this sometime ago (after last XMAS Party at oliver Springs) when my headlight elements (both dim and bright) burned out. I traveled with none for an hour or so at dusk.

My problem was just the bulb (both elements at the same time). I found the ibnfo in the first post online and sent for info. Just wanted to clarify that. 
Ride Country Roads - a lot. :-)