Electrical: All works except headlight & aux light

Hey folks.

When I got my bike the PO had started to put on the factory faring that usually comes with the saddle bags and all that jazz. Well, they never finished it and I don't want the darned thing.

Now, my bike is just about ready to get back on the road from being off the road since 1994. As I am getting it back to snuff, the electrical system is one of the last parts of the equation. I replaced the fuse box too, so no need to go there.

I have taken apart the bucket and all the wires inside it too. I have labeled everything that I can between the Haynes and chacal's wiring write up.

I have bypassed the relay to just see if I can get the headlight to light up. No dice. I presume that the purpose of the relay is to make sure that the bike starts and doesn't apply a load on it until the engine is running.

So that being said, the bike shouldn't have to be running in order to test the headlight, right? Bypassing the relay should mean that once the power is clicked on to the run position, the light should light up. Right?

 

Look up Looking for a wiring Diagram on this forum. MiCarl thoughtfully provided this link http://xjdiagrams.thundervalleypower.com/ for wiring diagrams. Head on over and read up on your schematic.

 

I had the non colored version of that one and it was hard to follow. I actually found a link to that exact same list but all the hyperlinks on the page linking to the files were dead! Thanks for including a good link though.

I will just go through the whole thing this weekend and take a looksey!

Thanks Robert.

 

I've been checking some things on the 750 SECA I recently bought and was also without a headlight when the key is turned on. I printed the schematics and list of numbered components, and seem to have traced my problem to the headlight relay. I got the cover off of the relay to have a look-see, and found that if I lightly push on the moving contact it will indeed light the headlight, and enable the aux light circuit, and the relay will stay contacted (closed) on it's own, and then release when the key is switched off. I wondered if the battery was up to snuff, so I hooked up a charger and was getting +/- 13.3 Volts which I would think should be enough to properly activate the coil in the relay on it's own, but it only will stay contacted if "helped", almost to the point of contact. I didn't have a good Ohm meter to check the coil's resistance (nor resistance spec to compair to) but I'm guessing I have a defective (weak) relay. Or, am I missing something?

 

Unless they've been modified, SECA 750's do not turn on the headlight when the key is turned on. The headlight doesn't come on until the engine is started. This is detected by a circuit that's triggered when the alternator starts generating power.

So: no headlight when key turned on = normal

no headlight after starting engine may mean that the alternator is not charging, the regulator is bad, or that the circuit triggered by the alternator is bad.... in addition to the usual suspects such as fuse, relay, and the lamp itself.

 

SQLGuy....Thanks! That tells me what I suspected. I'm not an electrical engineer but can read scematics pretty well and wondered if somehow the one lead being tied into a diode played into the picture, and that the engine had to be running and the charging system working. I don't know what might be in the diode or how that would pull the relay in by itself, but I'll guess for now that's the deal. I have the carbs off the bike right now so I can't start it, but was exploring other things on the bike until I have the time to go through the carbs and get them back on.

Thanks again!

Lynn