Author Topic: lamp issue vs headlight switch  (Read 1748 times)

Offline Eville Rich

  • Motobrick Curious
  • Posts: 28
lamp issue vs headlight switch
« on: June 30, 2018, 10:51:25 PM »

Now that I've bled the brakes, changed the oil (M1 15W-50), transmission and gear lube (Amsoil 75W-90), lubed the driveshaft splines, and adjusted the clutch cable, I'm tackling other little things on my new to me '87 K75S.

One of items on the list is a nonfunctioning high beam.  In reading about the issue, I see that there is a known problem with the highbeam switch wearing.  That was my first inclination.  But then I noticed that when I switch to highbeams, the dash indicator lights up.  This suggests to me that there may be a signal being sent, but the lamp itself is the issue. The light output just stays at the low beam level. I have not opened up the switch or wiring to test things - I'd like to avoid that in case I bugger it up myself. 

I'm not quite clear on the circuit to know if the dash indicator is triggered by the closing of the highbeam circuit or something else. Anyone have insight on whether having the high beam dash indicator light up means the switch is actually working?  I hope that's the case.  I think. 
FYI -if my switch is working, I'm going to get a relay wired in there to prevent burnout.

Thanks much,
Eville Rich
'87 K75S
'16 Yammie S10
'15 Yammie WR250R

  • WI, USA
  • 1987 K75S

Offline rbm

  • ^ Quintessential Motobricker
  • Posts: 2283
Re: lamp issue vs headlight switch
« Reply #1 on: July 01, 2018, 05:14:13 AM »
If the dash indicator is working, then the headlamp socket should also be getting power.  They are one and the same circuit. The highbeam problem is related to a bad H4 bulb or a bad H4 socket or faulty wiring between the switch and the bulb.  Test for power at the H4 socket, white wire.
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

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