'78 Turn Signal Wiring Diagram

[OldVet66]

Recently someone posted a reference to some wires that could be jumpered at the connector and an additional flasher installed for the other side of the turn signals. I didn't pay too much attention at the time, but my controller is getting unpredictable at times. If someone knows of this mod and could provide a wiring diagram I would really appreciate it. I couldn't find it again and didn't really understand exactly what was required to make this change.

[sedelen]

Think this could help!
Enjoy! 3 links in this thread should make you an expert!

http://www.thegsresources.com/_forum/showthread.php?t=186530

[SqDancerLynn1]

Cut the plug off the defective module connect the green and green/black wires together Connect the black to the black/red. Plug it back into the wiring harness.
Connect a flasher in series with the orange wire from the Turn signal switch Goes to red wire under tank ??? then to the fuse block . 2th fuse down ??

[sedelen]

So, what is the 1st Generation Turn Signal Control Unit not doing that makes you want to do this mod? Curious.

[OldVet66]

It works most of the time since I removed the self canceling wires, but at times the right signal will not work. I just want them to be 100% all of the time. I have gotten used to manually canceling the signal (Pavlov's Dog), so I won't miss that feature at all. I can deal with worn out flashers, connections and burnt out bulbs, but not a sealed unit with Gremlins.

[sedelen]

It works most of the time since I removed the self canceling wires, but at times the right signal will not work. I just want them to be 100% all of the time. I have gotten used to manually canceling the signal (Pavlov's Dog), so I won't miss that feature at all. I can deal with worn out flashers, connections and burnt out bulbs, but not a sealed unit with Gremlins.

Gremlins? Yes those TSCU units had a high failure rate. I collected quite a few, finally I got one that worked. I found many that flashed but wouldn't stop flashing. I have been looking all along and the pickin's have basically dried up. If I do pick up one I'll give you a PM, unless you should modify it beforehand.

This is the only one I know of available. Probably doesn't work since it's being listed as a CDI unit.

http://www.ebay.com/itm/200690176606?_trksid=p3984.m1423.l2649&item=200690176606&viewitem=&sspagename=STRK:MEWAX:IT&vxp=mtr

[Normk]

FWIW, my right signal was becoming intermittent so removed the cover on the turn signal control unit and checked for loose connections, bad solder, etc. in the section of the board which was visible. Noticed that touching some of the circuits caused the signal to cancel so, on the theory that moisture may provide enough conductivity to produce the problems, gave it a good spray with Fluid Film ( wax based anti-corrosion spray like LPs#3). Problem appears to be solved, but time will tell.

It is a simple enough modification requiring two normally open relays and one normally closed one to replace the signal light controller while retaining the original switching on a 1979 GS850G. A quick look at the wiring diagram confirmed the diagram made up in my head so if mine gives terminal problems will simply re-wire. It will do away with the automatic cancel but will retain the original switching and wires.

The normally closed relay would be connected in series with the signal flasher relay operated by the cancel switch which would ground the relay's winding to open the flasher circuit to turn off.

The normally open relays, one per side, would switch the signal circuit on for the side desired. The trick here is to connect the relay coil to the turn signal switch for that direction and to also include a jumper from the output switched contact to latch the relay. The cancel function opens the normally closed relay to shut off power and unlatch that side's relay.

This system would allow 4-way flashers if the signals were turned on both sides without cancelling the first side.

It would be possible to include a circuit to prevent the 4-way effect if desired but more complex and I like 4-ways in constuction zones on the ST1100 so would likely prefer that on the GS850G.

I may give some thought to adding a timer and pulse sense circuit to include automatic cancelling.

Likely someone has already posted both of these ideas here but can't find them if so.

[rustybronco]

https://www.thegsresources.com/_forum/attachment.php?attachmentid=15195&d=1323780825

http://www.thegsresources.com/_forum/showpost.php?p=1471473&postcount=21

Working on a replacement unit as we speak... (not done with it yet!)

[Normk]

Can't recall if a wiring diagram of a replacement circuit for the 1970 GS850G module was posted but can do so. My bike's left signal quit once in a while but seemed to have settled down after spraying the module with Fluid Film a few times.

When it did give trouble it would work again when I got to looking and was left with servicing the switches to see if there were obvious problems. When it quit today, was able to use a couple of bed-of-nails and ohmmeter to confirm that the switch and wiring were functioning down to the module. Time to replace the module.

I wanted to retain the original switches to maintain the original appearance and have the option of the headlight off switch so designed a circuit to utilize momentary on and cancellation. My circuit selects, redirects signal direction and cancels as did the original module but does not have the automatic cancellation. Not sure if it is wanted but will think about a simple/inexpensive solution to add that feature. I refer to wire colors in the module harness as the first step was to snip the wires a couple of inches from the module.

My circuit uses Bosch type relays as they are robust, inexpensive and in my parts boxes. I used one as normally closed to act as the cancellation, operated by grounding the terminal 85 by means of the handle bar cancellation switch by means of harness wire Brown/yellow (Brown with yellow tracer).

#86 is powered from relay terminal 30 to the orange harness wire. 30 provides power to the relay contacts in order to supply both signal directions.

Terminal 30 provides power to normally closed contacts to terminal 87a which powers terminal 30 of the other two relays.

The other two relays are normally open so only function when the direction switch selects one direction.

In order to use the momentary feature of the original signal switch, the two normally open relays are latched so that they remain closed. Cancellation is by energizing the winding of the normally closed relay to interrupt the circuit and unlatch the normally opened relay in question. In order to retain the redirection feature of the original system and so avoid the potential of having both signal directions in operation, each normally open relay has its magnetic winding grounded to the load side of the opposite relay. Of course a diode is required to avoid operation of both relays from one selection but anyone thinking of this circuit will have noted that immediately.

That should be sufficient for anyone to build the circuit but will post a roughly drawn diagram. If anyone is interested in understanding the operation of the circuit, I can post a series showing a build-up of the diagram.

Here's a photo of the completed modification:

[Normk]

Where's the photo??

Try again...

[Normk]

Here's a roughly drawn wiring diagram. I did it on the fly while figuring out the circuit in my head so that's why a couple of things are scribbled out such as the original intent to ground #86 at the cancellation (normally closed) relay.

[Normk]

Forgot to mention, it was necessary to disable the always on LED light panels used in the front turn signals because these grounded to the "hot side" of the signal wiring on the same side. The LED panels were switched power so stayed on all the time excepting when the ground potential was removed by the signal operation. In that mode, the front indicator LED panels flashed alternately with its own rear indicator. This wiring strategy does not work with the relay system previously posted. I will also be thinking of how I might retain that feature by the most simple means.

No idea if any of this is useful or of interest so will simply offer this much and see if more is wanted.

The same circuit could be used in order to operate direction signals by means of three push buttons (momentary switches) on any machine.