Turn signals only work when fuse is out?

I put new turn signals on my bike and replaced the relay with a digital one. Everything worked fine. Then the turn signals stopped working (they are on solid all the time but not blinking) so I checked the fuse and it was blown. No problem, I get a new fuse and out it in. Still nothing, but the the bike is ridable so I ignore t for a week. Last night I decided to tackle it and tried taking out the fuse.... AND THEY STARTED BLINKING!?..... but my tail light didn't work.

WTF? Black Magic?

What bike? What turn signals? LEDs? Which fuse? Which digital flasher?

It would probably be best to put the year, displacement, and letter designation for your bike in your signature to save you time later.

good call, sorry I wrote this late late night.

1978 Kz400 B1, 5 volt turn signals (not LED), Standard 10A turn signal fuse in original fuse box, Standard digital flasher from local auto parts store

Tmiron wrote: good call, sorry I wrote this late late night.

1978 Kz400 B1, 5 volt turn signals (not LED), Standard 10A turn signal fuse in original fuse box, Standard digital flasher from local auto parts store

Ok, I will try to locate a 78 400 B1 diagram. My manual only goes to 1977.

But in the meantime, are you sure the signals are 5v? How are they supposed to work on a 12v system?

Sorry I meant 5 watt

Sorry to get back so late, but I could not find a really good diagram for that bike. I'm using a small one where the text is difficult to read.

There is no fuse dedicated for the turn signals. According to the diagram, the signals get power from the main fuse, same as the ignition. If that fuse blows, the bike should not run, and the signals should not work. Someone may have done some creative wiring on your bike, so you will have to do some digging to separate factory wiring from the custom wiring.

Sorry, didn't realize you were looking for a diagram. There is one here:
kz400.com/Techh%20tips%20bilder/Wiring%2...s-canadianmodel2.jpg

There are 3 fuses. A 20amp (on the right in the diagram) for ignition, a 10amp (in the middle), and a 10amp (of the left) for turn signals, and tail light. Not sure what the middle one does.

It's very strange to me that the tail light works with the fuse in but signals won't flash. when I take the fuse out, the tail light stops working and the turn signals do flash.

One Other note: The digital flasher relay say that it requires a fuse (20 amp max). I've ruled this out in my head because initially when I installed it everything was working fine.

The middle one is the head light. I remembered that it was printed inside the box:

www.diablocycle.com/images/D/69_4232_fuse_3.jpg

So the main fuse is the one that fuses the signals, and that fuse never blew.

When the tail light fuse is out, the signals start flashing, otherwise they stay on. This could be because when the tail light is off, the battery voltage goes up just enough to let the signals start flashing.

It can be that the digital flasher requires a certain voltage to work. Or it can be that the ground connection is not great, and the tail light raises the ground connection on the rear signals, thus reducing their current enough to stop flashing.

Measure the voltage on the battery when the signals are flashing, and when they are on solid (tail light on).

Try to clean up the ground connections for the signals.

5W is less power than the original signals would have used, so they may be right on the edge of not using enough current to activate the flasher. It would be best to switch to a 3-prong digital flasher which will require adding a ground for the third prong. These work much better for low-power signals.

I put a digital flasher in mine last week. Same problem. I switched the wires around and it works fine. There must be a diode in there that regulates the flow that the thermal one doesn't and it happens to work backwards from original.

Hmm, you switched the two wires on the Digital Flasher Relay? I tried that, but I'll try it again when I leave work

I'll try a 3 prong if switching the wires doesn't work. Thanks!