Turn signals light but don't flash

[Jeff Adams]

Hi guys, I just finished swapping a complete 78 GS750 from a frame with no title to a titled frame. All together, but the turn signals all light but don't flash. Swapped out the flasher unit to no avail. Have checked the wiring against the diagram. Obviously I'm missing something, but what?

[GalDemSuga]

Perhaps a bad flasher unit? Do you have a known good one? I believe when I did my 82GS1100 I did a small mod. I got the info needed from BikeCliff's site.

[Redman]

A stock flasher requires a minimum amount of current to flash. THe current thru the flasher operates a heater, and the heater makes it flash (would take a long description to describe that).... if not enough current, then not enough heat to make it flash.

Possible causes:
- wrong bulbs of too low a wattage (I cant say what a 750 shuld have)
- maybe front bulb burnt out and you are looking at the rear, or visa versa. See that both back and front are on.
- charging system not working, and system voltage way too low. Check voltage to see that is much more than 12vdc.

[Jeff Adams]

Thanks for the info. The turn signals are after market and all 4 are new. I will check into that.

[Nessism]

If the signals use LED bulbs, the resistance will be too low to allow the flasher to function.

[Jeff Adams]

The turn signals are just regular automotive bulbs. Will the signals flash with just the key on, or does the engine have to be running?

[Rijko]

Engine does not have to run for the turn signals to work.
Did you check bulb wattage ?

Have one or more originals around to compare to ?

[Jeff Adams]

Not yet, but I will tomorrow, thanks

[Jeff Adams]

The bulbs are 10w, look like the old push in dash light bulbs from 60's cars.

[Rijko]

That's not enough.

The originals are 23W, so 46W total load is expected, not 20W ...

[Rob S.]

First thing I would try is switching out the bulbs.

[rphillips]

Seems he has very small bulbs. Thinking he won't find a bulb that small that will use 23 W. Seems time for different signals.

[Suzukian]

If you go LED you will have to add a Load Resistor to make the LED lights work.. I'm going through this right now with my '83 GS750ES. I ordered nice looking LED bulbs, but there isn't enough of a voltage drop to turn on the flasher. The 6 ohm sand block Resistor in a nice aluminum casing has the fittings to clamp across the two leads for each signal light, which will then trip the signal light relay. They are $16 bucks a piece though (Ouch!!). The 4 signal lights only cost $24 bucks. I am going to see if somehow I can wire the resistors at the source of the Flasher Relay to trick the flasher unit and get away with using one, or only two for the whole system. Fingers crossed.

[rphillips]

Surely it'd be easier to just wire in a flasher that's made to work with LED's... If you've got to have LED's.

[Jeff Adams]

Never thought about any of this when I bought the turn signal set off Ebay. They look like the originals but smaller.