R75/5 Turn signals

[GeezWhiz]

I'm having no luck in getting the turn signals to work on my '71 R75/5. The PO had hacked the front signals off to mount a Vetter fairing sometime in the dim past. During my rebuild, I replaced all the markers with new aftermarket items. All the wiring appears correct, the ground is good and the flasher relay clicks when the switch is activated both for the left and right lights. None of the lights flash, light up or glow. All the bulbs are good, 12v units. Doesn't it require a completed circuit for the relay to activate? If so, wouldn't that include the bulbs? I'm showing no voltage at the bulb socket or the junction block in the headlight bucket when the switch is on. Everything else electrical works perfectly. Ideas?

[bmweuro]

Those old 2 prong turn signal relays don't like to work below 12.5 volts. Rev the motor a bit and see if the flasher starts to work.

[GeezWhiz]

Originally Posted by bmweuro

Those old 2 prong turn signal relays don't like to work below 12.5 volts. Rev the motor a bit and see if the flasher starts to work.

Nope. I replaced the flasher without any success either. The turn signal relay is working. I can hear it clicking when I use the turn signal switch. Looking at the wiring diagram, it seems that would mean a completed circuit through the bulbs.

[bmweuro]

It's because the voltage going through it is to low. Charge the battery or rev the motor

[Bill Harris]

Make sure you are using a correct flasher unit--I've used a Buss #536 for years. The factory flasher is hideously expensive and some generic non-OEM units won't work right. The 2-prong flasher plugs into a 3-prong socket so make sure that the wires are connected correctly and are correct at the junction block below the flasher. You may need to just start tracing wires.

[ignatz72]

Are your aftermarket flashers LED?

[GeezWhiz]

Originally Posted by ignatz72

Are your aftermarket flashers LED?

Plain old filament style 12 volt bulbs with a brand new, fully charged battery. The system is charging and revving the motor just makes noise not light. I'm beginning to suspect the switch. I'll be checking all the related wires for continuity today.

[chasbmw]

The original flashers on your bike, would have depended on finding ground via the alloy flasher housing, stalk, steering head etc etc.

This is not a brilliant system, better to fit a ground wire from the indicator lamps into a grounding point in the headlamp. This might be the problem?

charles

[Uncle Pollo]

Originally Posted by bmweuro

Those old 2 prong turn signal relays don't like to work below 12.5 volts. Rev the motor a bit and see if the flasher starts to work.

get a modern relay like i did.