Topic: Help: 1976 750K left turn signals always ON

[hallin222]

OK, I've read several posts after searching these forums but haven't seen one with this unique situation. 

I had attempted switching to LED turn signals but have since abandoned that idea and am simply stuffing incandescent sockets (dual filament in from, single filament in rear) inside the mini bullet enclosures and tossing the LED boards aside. So, that LED flasher problem is gone.  I AM however still using an 'electronic' flasher realy from superbrightleds.com.

My current turn signal behavior is as follows:

RIGHT FRONT: one filament operates as running light, and the other flashes properly when switch is thrown (GOOD).

RIGHT REAR:  'off' normally, and flashes properly when switch is thrown (GOOD).

LEFT FRONT:  one filament operates as running light (GOOD), while the other is dimly lit (BAD).  Still flashes properly when switch is thrown (GOOD).

LEFT REAR:  the single filament is always lit (BAD) but still flahses properly when switch is thrown (GOOD).

I busted out my multimeter and have been studying the wiring diagram in my Clymer manual and here on this site:  http://data.sohc4.net/WD750/cb750A-1976.pdf and cannot see what is wrong.  The left side is wired exactly like the properly-functioning right.  I have discovered that the solid ORANGE wire for the left turn signals is getting about half voltage (7 volts) when it should be seeing ZERO.  Any ideas where this stray voltage may be coming from? 

[bollingball]

 Do the new signals have a separate ground wire? All the grounds tie in the bucket check them first. then check all the orange connections Then try your old flasher Then check the Sw. I use a electronic flasher with my stock signals and find they flash at idle just as good as at speed a good thing.

[hallin222]

Do the new signals have a separate ground wire? All the grounds tie in the bucket check them first. then check all the orange connections Then try your old flasher Then check the Sw. I use a electronic flasher with my stock signals and find they flash at idle just as good as at speed a good thing.

Yes, the new incandescent sockets are 3-wire front, 2-wire rear, and the fronts don't rely on the turn signal housingss contact to the headlight ears to 'self-ground' as the stock setup did.

I think my old (original / stock) flasher relay is toast, as it does not activate properly, and blinkers do not flash, but only come on solid (when switch is thrown) with it installed.  Also, removing the relay from the circuit does nothing, nor does jumping the relay leads.  The problem appears to be independent of the relay, otherwise, the right side would be acting up as well.

The fronts are currently grounded to the headlight mounting nuts/bolts and the rears are gorunded to the 4-plug ground connection in the rear (the same one that the tail/brake light is connect to).  The tail light and brake light work perfectly, and it too, is an aftermarket unit, and I have a BCR cafe tail on this bike.  All ground connections appear to be good.  I just can't figure out why the left side ORANGE wire is always 'hot' with half-voltage.

Double-checking ground connections now.........

[DarcyCB400F]

I have a detailed US/CDN model wiring diagram for a 400F that shows Orange, Orange White and Green wires in the left front signal.
Perhaps this will help??

[Spanner 1]

Turn signal switch IMO......... with ign. off, spray a good quality contact cleaner into the t/s switch while working it left and right, allow to dry a few mins. then try it..... use con. cleaner that leaves a lube behind, not the one that evaporates completely btw.

[hallin222]

Turn signal switch IMO......... with ign. off, spray a good quality contact cleaner into the t/s switch while working it left and right, allow to dry a few mins. then try it..... use con. cleaner that leaves a lube behind, not the one that evaporates completely btw.

That's what I thought too, so earlier I disassembled it to see if any of the factory solder points had flowed too far causing contact where there should be none.  I'll remove the little copper sliders from inside, clean everything thuroughly, and reassemble to see if that helps.  Stay tuned for updates.  *fingers crossed*

[TIM TINGEY, age 55]

MAKE SURE THE WIRES IN THE HEADLIGHT ARE PLUGGED TOGETHER CORRECTLY, THE ARE COLOR MATCHED SO THIS SHOULD BE SIMPLE. DO NOT USE ANY FLASHER RELAY AN ANALOG TYPE, THE BRIGHTLIGHT RELAYS ARE NOT GOING TO WORK CORRECTLY. THE BEST FLASHER RELAY ARE AVAILABLE AT KRAGEN OR SIMULAR AUTO PARTS. THEY ARE A VARIABLE LOAD 2 PRONG- ROUND BODY (ALITTLE BIGGER THAN A QUARTER). THEY WILL FLASH NO MATTER WHAT THE LOAD, EVEN IF YOU LOSE A REAR BLINKER THE FRONT ONE WILL FLASH AND SO ON. A DIM LIGHT USUALLY MEANS A POOR GROUND OR THE WRONG BULB, BUT A BAD RELAY WILL MAKE YOU CHASE YOUR TAIL. MAKE SURE THE GREEN GROUND WIRE IS BOLTED UP AND PLUGGED IN INSIDE THE HEADLIGHT (HDLT SHELL MOUNT). ALSO IS THE LEFT HANDLE BAR MULTISWITCH NEW OR THE ORIGINAL?, A POOR CONTACT INSIDE (WIRES LOOSE WHERE THEY WERE SOLDERED, OR BROKEN, FRAYED) COULD BE THE PROBLEM. THE SIMPLEST REASON THAT LIGHTS ON ALL THE TIME IS ITS PLUGGED IN TO THE WRONG POWER WIRE, OR THE RELAYS BAD. THE VARIABLE LOAD RELAY WILL ALLOW YOU TO RUN 1157  TALILIGHT BULBS UP IN ALL YOUR TUNSIGNALS ALSO.   

[hallin222]

I disassembled the left handlbars switch, and it didn't seem to help.  I was hoping some semi-conductive crud had built up in there.  No such luck.

All turn signal socket wires are connected to the proper colored leads from the main harness.  All grounds appear good.  I just can't find where these 7 volts are coming from on the left blinker (solid ORANGE )circuit.  I could try picking up a new relay at the auto parts store tonight, but since the light is on regardless of whether the relay is in the circuit or not, I don't think its the issue.

[DarcyCB400F]

Hi Hallin,
Somone smarter than me understands these relays and have posted recently some great advice on how to diagnose them. Search the forum and see what you can find... there is a topic here that addresses the realy in detail. "relay" or "flasher" or "winker"
I will see if I can find it too...
Darcy

this might help??
http://forums.sohc4.net/index.php?topic=82183.0