The bike only needs the ignition plug to run!

Well, I have been hunting around trying to figure out why my headlight is not getting any juice (SQLguy helped tremendously) and traced it from the fuse box to the big brown wire that runs to the ignition.

After I pulled the Atari off (thinking it went through there first) I noticed that i could start and run the bike with just the three pronged plug from the ignition to the main harness. Cool!

So this is where everyone else starts when they do custom work on these bikes, right? I am beginning to see that the wiring on Secas are over complicated, but simple enough to bypass.

Sorry...had to share my elation!

 

As a guy with an '82 that pulled the Atari, you are correct in thinking that 3-prong is the only thing (in that area) that makes the bike run electrically. I have a 2-prong Red/White to connect the battery sensor running off the key as well, but it's pretty useless without the Atari computer, and I also plan on going sealed battery next year. Someone here posted a minimum wiring diagram for these bikes, but I've lost track. You'd be surprised how little these bikes really need.

Welcome to custom. Make it yours and make a new kind of love for your machine.

 

Yeah, I can see the wisdom of keeping the Atari if the bike was maintained well enough through the years that everything functions. As of right now though, some of my wiring is just crap, so it ALMOST makes sense to just streamline the gauges and wiring on the bike.

What is more important to me is that in order to get this bike past inspection at the DMV, it looks like all I need is the headlight running, turn signals, rear running light and brake light. If that is indeed the case, I can get it legal MUCH faster than I was anticipating. Which means I can start saving gas MUCH faster than i was anticipating too!

Thanks for the encouragement.

 

If the Atari is working and all you need is to "FOOL" the Battery Sensor ... thats a piece of cake.

Run a Spliced-in wire:
From Tail Light (+12V Switched) -- To -- Sensor Wire (To Inst. Panel) -- adding a 2,000 Ohm Resister between the Tail Light and the Sensor Harness Wire.

)))>Tail>------>|-( 2KΩ Resistor )-|>------>| To Inst. Panel --Sensor |----

 

Mine is a headlight issue. The light works just fine so long as a jumper from the positive terminal to the blue/black in the relay. But all else, it fails. I think this has to do with the PO botching the heck out of a faring install.

But, I have no problem cutting away and making the bike a little more me and less 1983. Not that there is anything wrong with the year...I was 2 after all. Haha!

 

Well now I feel young, born in '86 here. Yes, my bike is 4 years older than I am.

As for the headlight issue, if you're going to chop the Atari you will have to remove the 3-prong plug from the Atari and put it into 3 different wires coming from the main harness. If/when you do that, might want to retrace your headlight wires entirely and fix the problem while you're in there.

 

Haha! I figured that would happen. Thanks for making me feel older!

As far as the headlight wiring...I want to do just that very thing. Replace all the wiring since as you pointed out it is all in the harness. But, I debate on what to do about the color coding. I suppose I could use one color wire and just label things REALLY well.

 

You could just use the wire colors coming from the low/high switch originally and put them directly into the plug, and pull a black ground from somewhere else. Per my Haynes book here, looks like you have a yellow wire for high and a green wire for low, going into a 6-prong plug for the Atari. That same 6-prong includes a black wire that I don't think is needed for anything else if you are pulling the Atari. Also, I believe the green/yellow wire going into that same 6-prong is your brake switch input, for when you bypass your brake light over. Hope this helps.

 

It does a ton! Thanks a million. Gonna attempt this tomorrow sometime.

Thanks!

 

This has NOTHING to do with the instrument cluster. It's saying that your fuse box is probably bad, AND, assuming the other tests were done correctly, that your headlight relay is also bad.

Even if you chop out the instrument cluster, you need to fix this/these issues.

If you remove the instrument cluster, do you not need some sort of speedo to pass DMV inspection?

 

SLQ is right on the money.

Before you begin any Electrical Troubleshooting; install a New Fuse Panel.
The Old Panels are dangerously unreliable.

Arm yourself with a Tool that will save you a great deal of time doing Electrical Troubleshooting on a +12V System.

http://www.rjtool.com/automotive-tools/ ... an-72.html

 

Paul/Rick,

You guys are both correct. I never tried to equate my headlight issue to the cluster. I do plan on bypassing the relay anyway and using a 20 Amp toggle switch just for ease.

In fact, I relate my headlight issue to the brown wire coming from the ignition wire that powers the accessories. I am ordering a new ATO fuse box to rewire the fuse box and create some room for other accessories when that time comes.

Once I get that in and soldered in place, I will begin to do some real trouble shooting. I do think my issues are due to the brown wire going to the headlight fuse.

But, while I was in there just giving a good visual to everything I figured out that it would run with just that three-prong loom connected. Thought it was cool. Gave me hope to ditch the Atari and go with some more "me" gauges.

I want you both to know I appreciate your efforts in this forum and definitely helping me out.

 

Speaking of gauges, I use a pair from mikesxs.com on this page...
http://www.mikesxs.net/products-46.html#products
I got numbers 03-0748 and 03-0675, both work great.

Oh, and I doubt if the brown wire itself is the issue, it powers a lot more than the headlight. Tracing only the headlight starts at the red/yellow wire heading for the relay. If I were you, I'd replace the fusebox then start working from that red/yellow wire.

SQL, not all of use have to do an inspection, I didn't.

Rick, I love those tools. Got myself one built to test home electrical wiring, uses batteries instead of the clip on the end.

 

My response about needing a speedometer was specific to MarshallNoise. However, even in states/cities that don't require inspections, an officer is usually free to write you up for non-functional or missing required equipment if/when you get pulled over for something else.

 

If anyone is curious, I just whipped out the multimeter and I have 11.8v at the brown wire coming off the ignition that goes to the red/yellow in the fuse box (headlight fuse).

The bike is not running at this point so don't sweat the voltages. Then nothing down at the red/yellow wire in the relay.

Me thinks the wire is shot and needs to be replaced.

 

11.8 should be close enough at this point to the fuse box. If the bike will run and you don't care about the aux light, this can be easily fixed. Just run a new wire from the fuse straight to the high/low switch and you should be fine. If you still want a switch to turn the headlights on and off, go ahead and run it into that new wire.

 

Thanks Mage! Yeah, I think I am going to wait for the switch and fuse box setup I just ordered. Then run a new wire from the fuse box up to the switch, then to the hi/lo as you suggested. Its just easier than dealing with the relay. Don't care about the fog light.

 

Hey Mage,

Bypassed the headlight relay and went straight to the blue/black wire under the tank in a 5-6 pin connector. Works great! Its just a temporary fix until the switch shows up. At which point I will just wire it down at the relay block.

I did try to take care of it with the stock wiring and couldn't get it to stop popping fuses. It specifically popped a fuse when I took out the blue/white wire and touched it to 12v. Since that runs to the diode block, I think that is where my problem is with the relay.

Good news is that the bike is not mint by any stretch of the imagination so I am not worried about it being original.

Thanks for all your help!

 

No problem. I'm not much of a wrencher, but being a computer nerd and former US Army helicopter avionics mechanic come in handy sometimes.

 

Ha! No kidding. Now the only weird thing is that when the low beam is on, the high beam bulb is on in the dash. I am sure it has something to do with the relay down there or I have a wire terminating into the wrong plug.

Either way, not a big deal. Eventually I am ditching the Atari anyway.

 

Yeah, you could always switch which wire the indicator light comes from with the new instruments. Why did Yamaha have to make such a mess of all this wiring?

Or go REALLY custom and change it into a "low beam indicator" light! You may have the only XJ with a "mod" light that!

 

Alright, that's enough. Just because some people can't take the time to understand it doesn't make it a "mess." Pretty much all the problems I've seen come down to bad connectors (because they're 25 years old and people have let water get in them and haven't renewed the electrical grease) or the stock fuse box (which is, admittedly, a weak point).

The headlight relay is there because it takes a decent amount of power to start the bike, and saving cranking current by leaving the headlight off makes starting it easier. An old starter with an old engine, and maybe an old battery and solenoid, is going to be harder to start, so that headlight relay functionality probably would have been a good thing to maintain. The high beam light doesn't just switch all by itself to showing things backwards, so it's probably not Yamaha's fault that Marshall's is now reversed. As for all the other "mess" on there... yes, I hear there are people who get along fine with hand signals instead of blinkers (probably still legal in many states), and without a horn (probably illegal in all states), and a side stand relay probably is entirely optional - but if you ever start off and catch yourself on the side stand and drop the bike, I bet you'll wish it were still hooked up. Even the warnings about the headlight or taillight being out are useful. I went riding with a friend just yesterday that didn't realize the taillight was out on his Warrior. Would you rather have a warning light on the dash, or a car running up on you because he couldn't tell you were braking?

If you want to complain about something on a Seca 750, complain about the master cylinder... that is a truly ridiculous contraption. If you can't figure out the wiring, then, of course it's your bike and feel free to "simplify" it until you can understand it, but don't blame Yamaha because you're not that good with electrical stuff.

End of rant. Fire away.

Paul

 

I'm totally behind you SQL. The wiring on these bikes is actually quite easy, difficult as that may be to believe. The biggest issue I've seen in electrical problems is a lack of understanding of the schematic and/or the components themselves. And there is no shame in being ignorant, we all start there. Taking the time to learn how to read a schematic and identifiying components will serve you well in the future so why not give it a go? Granted, old farts like me have years of experience at this but that is why we offer our assistance to those who want to educate themselves. So dig in and ask away, we're here to help.

 

It's not that I'm not good with the wiring, I'm just a student of the "simpler is better" mindset when it comes to electrical. Yes, the headlight relay has a purpose, never said it didn't. I just don't see why we can't just have 1 headlight power wire (going through the headlight relay) until you hit the switch, then it's 3 (including the high beam indicator).

I understand the wiring, just not the logic behind it.

 

I get all the warning indicators and even the idea of a relay that allows the bike to start before turning on the one major electrical drain. But, what I don't understand is why the exact same bike, the Maxim, doesn't have the headlight relay feature. If it is so valuable, why wouldn't they put it on ALL of their bikes?

The real reason is cost. The Seca was the flagship bike and got all the gadgets. Fine, fair enough. But 30 years later when a relay costs $80 on a bike that cost $450 to purchase it...seems to make more sense to ditch it and put in a switch that will be able to take the current for all of $3.50.

To me, my purpose of slimming down the wiring is precisely because it is a 30 year old bike that has had MANY owners before me and rarely taken great care of. Wiring goes bad, period. If you are lucky, you get a one or two owner bike that has been garage kept and even the fuse box is functioning properly. However, if you have to replace the fuse box, you can bet your keester that other wiring is going to be a problem too.

Hence, my problems. I don't want to chop my bike up and bob it. Rather, I want to get it on the road quickly and reliably. I see the excess wiring, 30 year old and weathered wiring, as a roadblock to my goal.

Now, it can be said that I gave this bike and it's stock wiring a fair shake at diagnosing it's issues, but there comes a time when you cut your losses. I am rapidly reaching that point.

I agree that the wiring isn't overly complicated. Reading the schematic isn't bad and it is pretty easy to trace things. I will find out my issues with the headlight indicator with little to no issues and I will want it to work properly. But the issue isn't the "complicated" way Yamaha did it, its that when the bike ages, the design is revealed to be slightly flawed in that it doesn't hold up well over time.

I appreciate all of the ol' sages around here and the purist mentality that seems to go along with the wisdom (save for Polak since he is a rebel in his own right). It makes for a great thriving community. In fact, just the fact that this place exists and there is interest in these legendary bikes is a testament to everyone who partakes.

In the end, let's just get along here.

/rant

 

Great post. I was under the impression that most Maxims didn't have the relay. Very interesting.

Good luck with yer body. I am waiting for the day that deferred maintenance catches up with me.

 

There are three wires going TO the headlight relay: one to supply power from the battery, one for ground, and one to tell the relay that the engine has been started. There is one wire coming out, that provides power to the headlight once the relay has been latched. How much simpler could you make a headlight relay?

After the relay, that one wire (Blue/Black), goes to the high/low switch, and two wires come out: Yellow for high beam, and Green for low. That's two wires, rather than the three you were suggesting... again, how much simpler could it be without losing functionality?

 

For one, I would like to know why we need that diode block. Or a sidestand relay. Why not just run the starter safety relay straight through the sidestand switch then put the clutch lever and neutral switch into a simple parallel wiring? And why is the self-cancel system wiring into the neutral switch? Then the sidestand relay is wired into the TCI box in 2 places...

 

1. The diode block provides a couple of different isolation functions.
1a. Rectifying one phase of alternator output to trigger the headlight relay when the engine starts while preventing the battery itself from latching the relay.
1b. Isolating the signals from the side stand and neutral switch so that the side stand down can display on the warning center, the neutral switch can light the neutral indicator lamp, and the TCI will be cut out if the bike is out of neutral and the clutch is released with the side stand down. Without diodes to isolate these signals you couldn't have two separate indications and the combined logic for the TCI cutout without additional switches.

2. The side stand relay is there because they're doing a couple of different things based on side stand state combined with clutch and neutral state. One being to prevent starting in gear without disengaging the clutch and the side stand, the other being the previously mentioned TCI cutout. If they hadn't added the requirement that the side stand be up to start in gear, then they wouldn't have needed the relay. They probably could have added one or two more diodes instead of the relay, but they couldn't have had the same logic with less components.

3. The self-cancel circuit does not wire into the neutral switch.

4. The side-stand relay connects to the TCI in only one place: the Black/White cutout line.

Keep in mind that Black is ground. TCI has a ground, the side stand relay has a ground, the cancelling unit has a ground, but the fact that most things need ground does not mean they're sharing signals.