Turn signal control unit

[Stalin]

I got a 1979 GS850 from a friend last fall. Lots of things to fix. Lately i tried to get my turn signals to work properly in order to get it approved by the swedish DMV. It would flash, but once i release the switch it stops blinking. Very annoying and illegal over here. I read on this forum that the GS has this control unit. Expensive, hard to find and seldom works. According to a wiring diagram the unit was connected by one 4-pin and one 6-pin connector. I followed the harness and found out the whole unit was removed and replaced by a couple of jumpers. No wonder it didn't work as expected. More forum surfing lead me to someone who constructed a digital unit built up on a micro controller and a timer circuit but i couldn't figure out how to program such a thing so i made up a cheap workaround based on simple 12v relays. The auto-cancelling feature is gone but i can live without it. This is how it works:Each side (L and R) requires 2 relays: one for the "hold circuit" and one to actually let flash signal thru. Then the blinkers wont stop, so we need one more relay for the cancel function. This sums up to 5 relays where the first four are simplest on-off and the cancel-relay has to be a switch because it will feed the others with 12v when its not active and break the circuit when hitting the cancel switch. Therefore the cancel relay must have the 87a pin. So pushing the momentary switch on the handlebar to the left will cause a pulse that makes the first relay to switch on and then feed its own coil in a hold function. At the same time the second relay will switch on and lead the flash signal to left-hand lamps and indicators. The fifth relay has a constant +12V on its control coil, and also on pin 30. Cancel switch is basically a momentary ground wire that completes the control circuit causing the relay to switch and stop feeding 12V into the first two relays. I just bought cheap generic 12v relays, taped them together, soldered the connectors and some jumpers and it works perfect on my GS.

 

[Stalin]

I Apologize for my poorly drawn diagram. First time using an on-line editor. Hard to find the right symbols.

 

[Nessism]

Nice work and thanks for posting!

 

[Guest]

Very interesting, and yest thanks for posting.

 

[posplayr]

Are we talking about an alternative to this (sans Auto cancel)?

http://www.thegsresources.com/_foru...SCU-quot-banging-the-bits-quot&highlight=TSCU

 

[Stalin]

Yes. Thats the one.

 

[Guest]

So I'm not the best at reading the schematic diagrams. Do you have anymore pictures and information about this whole thing?
Do all the relays have to be 5 pronged? Seems like 4 of them only need 4 prongs.
Also, other than being 12v does the relay need to be any specific kind? Looks like some are $30 a pop which isn't very cheap when you buy 5 of them.
What does the rectangle box with a line curling around it in the diagram mean?

 

[rustybronco]

Do all the relays have to be 5 pronged? Seems like 4 of them only need 4 prongs.

All of them can be four pronged. The cancel would need to be a Normally Closed relay

Also, other than being 12v does the relay need to be any specific kind?

Just something durable.

What does the rectangle box with a line curling around it in the diagram mean?

That is the solenoid portion of the relay.

You can also do the same thing with just three relays.
www.thegsresources.com/_forum/attachment.php?attachmentid=15195&d=1323780825

 

[Guest]

Awesome. Thanks!

So with this three relay system I need two 6 pronged relays and one 4 pronged relay, correct?
I understand 75% of this diagram so I'm going to go ahead and buy the materials and get started.
I'm probably going to have a few more questions though.

 

[rustybronco]

Yes, but the 4 pronged relays are easier to obtain. In fact I have a pile of them.

 

[Stalin]

Yes Rustybronco (and Tanerrc) I used these relays because they were cheap and easy to get. Less than 5 dollars each in our PepBoys-type-store. And i already had a couple of them at home.
So you need 4 relays with 4 terminals (normally open) OR 2 of the more sophiticated shown in the other thread.
In addition, for the cancel function you need 1 normally closed OR as in my example switching relay. Hence the 5 terminals as it will switch between two of the output terminals, and you still only need do connect 4.
Good luck, Tannerc! questions are welcome

 

[Guest]

So I followed the wiring diagram the best I could but this thing isn't working right. It'll turn on my left turn signal and it will stay on (not blinking) until I hit the manual cancel switch. The right signal will turn on and stay on (not blinking) but won't turn off when I hit the manual cancel switch.

Can anyone help me out? Not really sure where to go from here.

I'm assuming something is wrong with the cancel relay so I put a picture of it up here.

 

[mikerophone]

This is great - I have 3) 850's right now and 2 of them have iffy TSCU's, the cheapest one I've found was $50 on eBay and it was gone the next day.

I might have have missed it but does this retain the self canceling feature?

 

[posplayr]

This is great - I have 3) 850's right now and 2 of them have iffy TSCU's, the cheapest one I've found was $50 on eBay and it was gone the next day.

I might have have missed it but does this retain the self canceling feature?

From Stalin (OP)

The auto-cancelling feature is gone but i can live without it.

 

[bodin62]

Hi I am new to this forum and I was looking at the drawing and can not figure it out. I looked at the picture of the 5 relays wired, but do you have a diagram with colors of wires that corresponds
to the picture. On the diagram where wires cross and there is a dot does this mean that the wires are soldered together?

 

[Stalin]

Hi bodin62. Sorry, i sold my GS so i forgot to look back to this forum.
In the diagram i have written out the colors on the wires. On my 850 they match the colors in the old diagram for the whole bike.
In my diagram, if two lines are crossed it does not mean they are connected to each other. However if there is a dot where they cross it means connected.

Tanerrc. Your cancelling relay seems to be soldered exactly the way i did it. Maybe you could try moving from 87a to 87 if your relay is working "normally connected"
--Stalin

 

[bodin62]

Thanks for the reply. Once I get the relays I will try to wire it up according to your diagram.
I did look up the price for a new control unit and it was around $400, so your work around is a lot less expensive.

 

[Bikemessenger]

I'm too having problems with the turn signal on my 1982. The right signal works fine when slid to the right, but it doesn't shut off automatically after I make my turn. My left turn signal on the other hand works intermittently. I pull it left and most of the time it doesn't come on. Instead, I usually have to wiggle it back and forth with my thumb a few times to make it come on. I'm usually halfway through the turn I was trying to signal before I can get it working correctly. The left signal does shut off though after I finish the turn.

So can these units be disassembled and rebuilt or should I just buy another setup on Ebay?

 

[Guest]

So I'm back to trying to get this thing to work. I noticed a mistake I made in the wiring and now I'm a bit closer. Both signals behave the same now but still don't work properly. I can get the left to come on and stay on not blinking and same with the right. If I make the switch go left and then right without canceling the signal in between, then both sides will flash like hazard lights.

I tried switching the cancel wire to 87 on the cancel relay instead of 87A but the signal would just turn on not blinking and turn off as soon as i released the switch. I'm not sure what "normally connected" means either.

I'v gone over the diagram a bunch of times now to make sure my wiring correct and I think it it. It's so close but I'm not sure what to do from here.

 

[Guest]

So I've triple checked everything and I'm sure I've got my wiring set up just like on your diagram. Is there any chance that the signal relay that is already on the bike, you know separate from the 5 that I've wired together, has gone bad and that is why the signals aren't working. I've got the lights to blink just not the right way so I"m assuming that means the signal relay is working. I should also mention that the turn signals aren't stock but I'm 90% sure they worked with the old TSCU before it crapped out.

Any help is appreciated.