Ground Locations? Turn Signal Fuse blowing?

[MagicAttack]

I have my turn signal fuse constantly blowing when I ride for more than 30 minutes. I've tried to identify what exactly causes it to blow, but nothing specific or consistent has been found. I only notice that sometimes at a stop light, my signal lights stop flashing (as if I pushed in the button), but resume as normal if I press it again. Also, I have noticed that when I do have my signals going, and I'm in neutral, my neutral light dims in consistent with the signal, as if I'm drawing not enough power through the circuit. 

So I think, could be wrong of course, but think I am chasing a ground. But I must be blind cuz I have pulled every piece (I think) and have found maybe two ground total, knowing there must be many more. Any help?

[djh3]

A dim light would lean towards a failing ground or possibly low voltage. If a fuse is blowing its a direct short. Power to a ground directly without going to the load (light, electric motor etc)

[saddlebum]

1. does it happen only on left or right or both?
2. does it matter if handlebars are straight ahead or when they are turned ? (if only occurs while turning handlebars check for wiring fault in and around steering head and handle bars)
3. With the bike parked and turning turn signals on first right and then left does one of the lights appear dimmer than the others? (check for wiring fault or short to ground in wiring feeding the dimmer bulb )
4. Check for a faulty bulb specially the dual filament  bulbs in front ( they have been known to develop an internal short across the dual filaments strong enough to blow fuse and often times this issue can be intermittent.
5. Check wiring around steering head going up to cluster for possible chaffing
6.  Follow the front signal light wires to a 6 pin connector with only 5 pins used I think it may be a blue connector and pull connector apart. Retry using your signals if issue went away the issue is between that connector and signals. Go to step 7.   If it is still there wiring from connector to  signals is OK. Go to step 8.
7. Disconnect connector at rear going to rear lights. (if issue goes away check wiring to rear lights if still there check forward upstream of connector).
8. Check wiring between blue connector and handle bar switch.

 

99-09 Yamaha Royal Star Venture schematic.pdf

Edited June 4, 2021 by saddlebum

[videoarizona]

Also check the ground of the horn by your right foot.

[MagicAttack]

Okay, well I may have narrowed it down, symptom-wise, just need to get into it tomorrow. I've noticed that it doesn't blow when my turn signals are going, only when I am putting it into neutral. It'll blow only when going in between neutral, if it blows at all. I went on a long highway ride with no issues, but as soon as I started hitting traffic lights, popped it went. Does neutral switch run through the signal circuit, or just the dash light?

[saddlebum]

The neutral switch is a grounding switch in other words instead of switching the 12 vlt pos side of a circuit it switches the ground side of a circuit on/off. Because of that the switch itself cannot cause a fuse to blow if it were shorted to ground. instead if it were shorted to ground the neutral light would stay on all the time. However if the brown wire from the signal fuse was shorted across to the light/green wire to the neutral as in having rubbed together somewhere in the circuit this would blow the signal fuse. As you can see in the schematic the neutral switch also provides ground signal for the carb heater relay, the starting circuit and the igniter unit as well as the neutral light.

1. Carb heater relay - disconect relay and/or connector to see if issue continues
2. disconnect connector at relay connect test light or voltmeter to ground and test for currant at light green wire on connector it should light up or show voltage.
3. disconnect eight pin connector at igniter unit, carb heater relay, and 12 pin connector at starting circuit cut off relay assembly. recheck for voltage as in test #2. if no voltage  this time circuit should be Ok. If there is voltage go to test #4
4. While performing voltage check as in test #2 remove signal fuse. If indication of voltage goes away there  the light green wire from the neutral switch and the brown wire from the signal fuse have shorted together somewhere in the circuit.

Edited June 5, 2021 by saddlebum

[circa1968]

In looking at the wiring schematic, the following are on the load side of your turn signal fuse:  Horns, flasher relay, hazard relay, most of your dash indicators and the Brake Light Relay.  The neutral switch is on the carb heater fuse, so this could be a red herring.

Based on your symptoms, I suspect the Brake light relay likely has a fault in it causing at least a partial short to ground when applying the brake (while in traffic).  If the fuse blows when in traffic or neutral, you are also likely braking.  A ground fault in the relay when braking would effectively rob voltage from the rest of the signal circuit and this would explain the neutral light dimming.  Its probably not a hard short to ground but enough to cause the light dimming and then eventually a blown fuse.

This is definitely not the only possibility, but a good candidate based on symptoms and what is on that fuse circuit. 

[circa1968]

Oh, also check your brake light itself to make sure it is working properly, the fault could also be on the other side of that relay.  The relay contact is fed power via the brown wire (straight from the fuse) and once the relay is energized, or closed, the yellow wire receives power and sends it to the brake light.  A ground fault anywhere along those two paths seems like it would cause your symptoms.