Not enough voltage to headlight relay coil

I really hate to post this, but I haven't bought a Chiltons yet so have no access to a decent wiring diagram.

I took apart my headlight relay and gave it a good cleaning. Now with the key on I can push the contact over and it'll stick and light up the headlight.

The problem is that for some reason I'm barely getting any voltage to the relay coil... causing it not to activate. I've looked at the diode pack (not torn it apart) and it doesn't look melted. I've replaced the melty fuse block, so everything is good there.


Does anyone know what else I can test or look at to figure out why I'm not getting enough voltage to activate the headlight relay?


Thanks!

 

Whn are you taking this voltage measurement? The system is designed to keep the headlight OFF until the engine has "started", meaning that the engine (and thus the alternator) is producing a certain level of voltage (exact amount unknown).

If, with the engine running, there is not enough voltage on the trigger wire (which is fed by one of the three white wires from the stator), then it means that the stator leg is "weak", or the diode block (which the current travel through before reaching the relay) is not functioning properly......

 

I've been taking the measurement with the key on but the bike not running. I was under the impression from reading around that the headlight would come on any time the key was in the on position, go out while the starter is running, then come back on once the bike had started.

I've got my gas tank off right now so the best I could muster was a few quick rough idles around 1000k rpm, but I wasn't measuring at that point and now I'm out of gas. Either way it wasn't kicking the relay on.


In the meantime is there a suggested way to check the stator leg and diode block for proper functionality?

 

That is not correct..........the headlight relay will not latch on until it receives a sufficient triggering voltage due to power being generated by the altenator (the lower the rpms, the less current the alternator outputs).

Once enough voltage is received by the relay, it latches on,, andallows the headlight to come on. And the headlight will remain on untilt he key is turned off (all power cut to the relay) since it is a "latching" relay......


Diodes are "one-way" electical "valves", so testing the diode block simply means you check for continuity, it should pass current in one direction and not in the other direction.

The actual schematics on the checking procedure are too long to repeat here; you'll have to wait until your manual arrives!

 

Alrighty, thanks for the info. Hopefully i'll get lucky and it'll decide to latch with enough RPMS, if not i'll resort to the manual