Headlight / turn signal one sided problem

[methman]

After R/R problem (solved) I have got another one on my VFR800 (1998, German spec.). It has HL switch on the right handlebar.

To make long story short, when  I switch on headlights, turn signals do not work, when I switch off the headlights turn signals work.

If HLs are on:

- right side H4 is dimmed (kinda neon lamp),

- left side H4 is on full,

- left TS does not light at all, no sound from TS relay

- right TS, no light, TS relay makes bzzz.

 

Changed TS relay - no change. Star ground clean.

 

I measured resistances (with no bulbs connected):

left HL / right HL - blue 0.1 ohm, green 6.1 ohm, Wh/Bu 0.2 ohm. Day before harness fiddling it was 0.8 to 1.3 ohm for Gr/Gr difference.

HL relay Gr-Bu (coil) 104 ohm ... relays seems to work properly. The same for Hi beam, and TS relay.  

Gr/Gr HL-TS on the same side 0.1 ohm.

 

Made more measurements, but those seems to be weird. I can make other, if needed.

 

My bet is on the bad grounding. My problem is that I do not know, how to repair it, because the all "greens" goes to main harness. But maybe I am wrong and you have met this kind of problem before ..... Thing could be more intricate than it seems. So your help will be appreciated.

Thank you in advance. 

 

Tom

[Mohawk]

Why has it got a H/L switch on right bar ? That is normally on the left bar, did you say right in error ? Do you mean the lights Off/side/dip selector switch ?

 

As you state all grounds feed back to the rear left connectors block in the harness near the RR. Mine did many weird things & when I checked the block having peeled it out of the loom wrap tape it all looked good. But when I removed the crimp connectors from the block approx 50% of the wires  were furred up with green copper oxidation in the crimps. So I cut the all out & cleaned the individual strands, then bulk soldered them & the weird electrical issues went away. 
 

YMMV

 

[methman]

H/L switch. Do you mean Hi / Lo beam? It is on the left. On the right there is a triple pole slide switch: Off - position light (small bulb in the middle of headlight) - On (both H4 bulbs).

The block you are writing about, is it a 4P Black connector between batery ang R/R?

[Terry]

I think our Czech friend is referring to a headlight (HL) switch, which probably has off, park and on as choices? It's been a while since I had a bike with that switch. 

 

I'd still be looking at an earthing fault as a likely cause, as the headlights and turn signals share a common earth; if there is excessive resistance then current flow is restricted, and then insufficient to run both headlights and turn signals, and insufficient to make the turn signal relay work. 

 

[Mohawk]

5 hours ago, methman said:

H/L switch. Do you mean Hi / Lo beam? It is on the left. On the right there is a triple pole slide switch: Off - position light (small bulb in the middle of headlight) - On (both H4 bulbs).

The block you are writing about, is it a 4P Black connector between batery ang R/R?

OK we are talking about the same thing 👍 Yes wrapped in the wiring loom near the RR is a multi-block  where all the Earth return wires terminate. 

[methman]

9 hours ago, Mohawk said:

... Yes wrapped in the wiring loom near the RR is a multi-block  where all the Earth return wires terminate. 

Thank you. This is what I have been looking for. The junction! Hopefully, I will find time in the evening.

[methman]

Thank 

On 9/9/2025 at 10:47 PM, Mohawk said:

Yes wrapped in the wiring loom near the RR is a multi-block  where all the Earth return wires terminate.

 

Problem found there, thank you.