Reserve Lighting Unit Toasted?

[randy]

Hi, Guys.

Thought I'd run this one by all of you before I start pulling Swamp Thing apart to run this gremlin.

My understanding of the operation of the Reserve Lighting Unit is:

With a normal headlight, all OK =

-headlamp indicator light on.

When headlamp blows out =

-headlamp indicator goes dark.
-high beam indicator comes on.
-high beam filament is lit at lower than normal voltage to take the place of the normal headlamp...

I hope that's correct, so here is my symptom:

The high beam indicator will come on by itself.
The high beam filament is lit as if the low beam filament failed.
The headlamp indicator remains lit.
The low beam filament is dark.

For no apparent reason this symptom comes and goes.

Any ideas, guys? And I don't mean try this...try that. Have any of you encountered this very symptom, and if you did, what was the remedy?

Thanks in advance.

Randy

[TopCatGr58]

Hey Randy,

My, getting picky in our help requests aren't we!!??

Well, I'm pretty sure My headlight indicator ISN'T on all the time!!
I was pretty sure it was ONLY supposed to come on when the Headlamp is burnt out, to warn you that it's out! Most of our idiot lights come on when things are bad, not to be on when things are working right!?

If either headlight filament burns out, the other filament will come on and the indicator will come on.

So,....I was looking at the Clymer's wiring diagram and I think I see where your confusion comes from, the diagram looks to be incorrect!! It shows a tan colored wire coming directly from the fuse block, that is linked with the horn, neutral, front and rear brake light switches. So...you would assume that this light comes on when the ignition is on!?

However, in the 80-81 Clymer's diagram, there is a light green wire that goes to the Headlamp warning light which comes from the Reserve lighting unit. And as best as I can follow it, the OEM wiring diagram for the 78E on the Yamaha Parts Catalog Service data also shows a light green wire from the Reserve lighting unit to the indicator lights, but they don't show which wire goes to which bulb!!

So, it really looks like you have a fried low beam bulb! Have you taken a bypass 12V power wire to that bulb contact to see if it will light? Or a gauge(duh) and checked the continuity of the low beam prong on your bulb?! Also try shaking the bulb! You could have a loose/hanging filament that is sometimes making contact in the bulb!?

Not trying to get you upset, just trying to help!? T.C.

[randy]

T.C.;

No harm intended by the precise request, I just hate to start ripping in to electrical gremlins without a clear idea of the troubleshooting route.

I knew the Clymer's schematic was wrong, which means that I had a good chance of doing more harm than good without a roadmap!

I could just route around the RLU, but I'm a purist where these things are concerned. If the bike came with it, I want to keep it.

BTW, my filaments are good, so I guess I had a bad RLU all along. My headlamp indicator was always lit from the very first test run way back in June!

Thanks again


Randy

[rover]

rlu

If you want one, pm me with your email addy and I'll send you one.

[John]

Randy. I have had the priviledge of having a working RLU do it's thing. On my bike , the RLU lamp just has a faint glow when all is well, and it will light up brightly when it's doin' it's thing. The headlight will be too dim to see very well, but you can use high beams when needed, then dim down till the cars pass.

[pgg]

Randy and John, isn't it obvious? You're both in the unenviable position of owning the 'special' model rather than the superior 'standard' model.

Trouble can be expected.

Trade up to a standard to fix the problems.

Uh-oh I feel this thread turning like NZ's current sea conditions - ugly and out of control.

Must quickly sign off now - I suddenly have urgent business elsewhere.

[randy]

ppg;

Wrong, you are!. I have a standard, 79F. But that's beside the point.

John, seems that my RLU is 'doin it's thing' even though I have a good headlamp, both filaments are good. That's why I think its roasted.

A very kind member has offered a spare RLU for me to swap. It's on it's way to me right now.

Randy

[John]

Originally posted by pgg
Randy and John, isn't it obvious? You're both in the unenviable position of owning the 'special' model rather than the superior 'standard' model.

Trouble can be expected.

Trade up to a standard to fix the problems.

Uh-oh I feel this thread turning like NZ's current sea conditions - ugly and out of control.

Must quickly sign off now - I suddenly have urgent business elsewhere.

Don't you have some carbs to clean, or something
Specials Rock!

[ARRON]

i bought the manual for the xs's from yamaha,the manual says the light should be on (dim) all the time,when everything is ok

[randy]

Thanks to rover

Thank you, rover for the RLU. All is working fine now.

Randy