headlight relay

[oldyam80sg]

If the headlight relay is bad will the lights still come on on my 80 SG? or will the reserve headlight system do anything if the relay is bad?

[John]

The headlight will not come on if the relay is bad. You can by pass it, or you can use a more common Bosch relay, and hook an oil pressure switch to it to allow it to be on only when the engine is running. The RLU will not do anything to make it work if the relay is bad.

[oldyam80sg]

What controls the gauge lights do they come on also when the headlight is on?

[TopCatGr58]

The gauge lights usually come on with the tail lights, when you turn the ignition key on.
T.C.

[John]

The gauge lights are powered by the tail light fuse from what I can tell from my manual.

[oldyam80sg]

I'll check that out tomorrow.I did get the turn signals working by cleaning the contacts and reinstalling the old flasher.Now if i can get the headlight,lights in the gauges and oil pressure light to work,i might be able to ride it soon.Thanks

[oldyam80sg]

If i use a Bosch relay or any other relay for that matter-can i get it at an auto parts store?.If i can what am i looking for.Is it a normal headlight relay?

[John]

If you use a Bosch relay, then you will need to power the relay with 12v from a source that is hot only when the engine is running. A 5 psi oil pressure switch would work. Just order a four prong relay that has the terminal numbers of 30, 85, 86, and 87. 30 and 87 will be the power to the head light, and 85 & 86 will be the circuit that energizes the relay from the OP switch.

[DJinNH]

John,

thanks from me too. I've got my SG all up and running now...finally, but the headlight and instrument lights won't come on. Sounds like the same issue so I'll check the relay. I already checked the connections in the light itself.

Everything else works fine; directionals, neutral light, brake light.

Don

[DJinNH]

Round 1: man, I checked every wire connection, every fuse that I could find and even pulled apart the headlight.....no luck.

I even checked for power following along the green and the black wires using one of those power pics (lights up when you stick it in the power source...yes, I remembered to ground it.) No power showing even way back above the battery with that wire connection and key turned on.

I'll have to dig again and check that relay and maybe do a bypass.

Wish I had a pro here to point things out as I am struggling through this surgery with the repair book.



Don

[oldyam80sg]

If it makes you feel any better i still don't have headlights either.I checked everything multiple times.I have a relay and wiring harness coming next week but was hoping on riding today or tomorrow.

[John]

Just jumper around the relay. The only catch here is that the light will be on when ever the key is on, and also when it's cranking over.