Headlight / turn signal one sided problem

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

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

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?

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. 

5 hours ago, 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?

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. 

9 hours ago, Mohawk

... 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.

Thank 

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

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.