Maxim 550: Headlight not working

My apologizes in advance if this has been discussed before, my search-fu didn't turn up much. I picked up a Maxim 550 as a project bike which is proving to be way more of a project than I had anticipated. I spent a good hour this morning poking around trying to figure out why the headlight isn't working but to no avail. The PO had replaced the fusebox with a homebrew tangle of wiring so I'm a little in the dark trying to trace wires and what not. I do get resistance (~1 ohm) at the bulb terminals so I believe it is good, but no headlight or instrument lights. I do have the brake light and turn signals + neutral light on the panel working. Could anyone provide some suggestions on where to start tracing this? Anyone have pictures of their under seat area to point me in the direction of the headlight wiring/hardware (at least where it should be running)?

 

Did you check the relay for the headlight?

 

Unless I'm reading this wiring diagram completely wrong (entirely possible), the headlight relay also powers the brake lights and turn signals, which work.

 

I think you are reading the diagram wrong. The headlight relay is activated by the output from the alternator, the brake and signals operate when the key is turned on and the appropriate switch is activated. Diagram to follow.

 

Diagram...



The colours on the diagram are the colours of the wires.

 

You wouldn't have a circuit diagram as well, would you?

 

lbarber ... your last question is informative, you need to understand the circuit first, to figure out how it works, then go to the correct WIRING diagram to figure out how it has been WIRED up on your machine. The wiring diagrams are very confusing if you are trying to understand how a circuit works, but are essential for troubleshooting once that is clear.

Your first step should be to obtain the correct FACTORY manuals and supplements if applicable, these include both circuit and wiring diagrams in the back and a host of other good information.

There are several sources for the manuals, CD's you can buy, online pdf's you can find with google and download, and there's a number of posts on this forum which refer to these sources. Here's where I got mine

http://www.4shared.com/dir/DVtAfjvr/onl%20ine.html

there's bound to be others.

When you have that information try this to help you at least get your head around where to start looking ....

http://www.xjbikes.com/Forums/viewtopic/t=32483.html

Good luck with it, come back if you need more assistance

 

Before jumping into the headlight circuit lets ask some questions. Did the light work at one time then stop? Is the bike running or are you just in the process of getting it running? If the bike runs, does the charging system work? If the answer to all of these is yes. Lets proceed. If the answer is no to one or all then we need to change our thinking.

Assuming the answer is yes to all...If you have a test light probe the relay.

The orange and brown wire is 12 volts when the key is turned on. If there isn't 12 volts here, the fuse or wiring could be at fault

The black wire is negative and eventually connects to the frame. To check this wire connect the test light lead to the positive terminal of the battery and then probe the black wire. The light will come on if the if the circuit to ground is good.

The white wire is fed voltage when the alternator starts producing voltage. This wire is connected to the diode block. The light should come on once the engine is started. If not , the alt. or diode are faulty.

The remaining wire feeds 12 volts to the headlight switch once the white wire is powered. It also should come on once the engine is started. If not the relay is faulty.

 

Just a really quick question:

IS THE BIKE RUNNING?

If everything is functioning correctly, the headlight will not come on until the bike is running. Then it should stay on, even if the motor stalls, until you turn the ignition off.

From what I was reading, you're "static testing" and nobody asked the obvious...

 

I guess I went the roundabout way to ask the question.

 

I'm worried we're trying to "fix" normal operation.

 

Fitz-
Yes, the bike is running. Not running very well, but it does run. Digging into some of the smaller gremlins this week before taking the plunge and checking the valve clearances this weekend (from what I read you're pretty big on getting that done). :mrgreen:

 

I meant, is it running when you want the headlight to be on? The headlight will not come on if the engine isn't running; it comes on a split second after the motor fires, because the headlight relay gets its "turn on" signal from the alternator.

I wanted to be sure you weren't looking for the headlight to come on with the other lights, just by turning the key on. It shouldn't.

Valve clearances are important because if they aren't in spec, carb synchronization is next to impossible. I keep bringing it up because people are afraid of it, so they attack their carbs FIRST and then can't get them re-adjusted right; rather than doing everything in order, which means valves first. Also, because a way-too-tight valve is getting very close to actually DAMAGING the motor; damage that could easily be prevented by simply staying current on required maintenance.

 

Well it took a lot longer than I thought, but I'm back to the headlight. I don't know what on earth the PO did to the wiring on this bike, but for the life of me I can't even find the headlight relay...and based on the loose connector under the tank I just found I'm wondering if its just not there at all. Am I correct that the relay should be plugged in to this:

_LTB3918.jpg by ltbarber, on Flickr

Also, what is this mystery box?


_LTB3919.jpg by ltbarber, on Flickr

 

That looks like it is the connector for the headlight relay, a little hard to tell the exact colors from the photo:

Headlight Relay:

Location:
- on all XJ550 models: under the gas tank, in-between the frame tubes, on a welded bracket just behind the flasher self-canceller relay.


Identification:
- small metal "cube" relay, inked 3H5-00 on the top face.
- has a yellow (yellow) paint mark on the bottom terminal connector block.
- normally open; has an internal diode.
- plugs into a connector shell which has the following set of wires going to it:

Harness connector wire colors:
- on all XJ550 all models, XJ650 all models (except Turbo):
* Blue wire with black tracer stripe
* solid White wire
* Red wire with yellow tracer stripe
* solid Black wire



The long rectangular, rubber-covered relay is teh turn signal self-canceller unit.

 

If that red-looking wire is actually red with a yellow stripe, then that is the headlight relay connector.

Assuming that it is, jumpering (like taking a piece of insulated wire, stripping the ends, and pushing them into the connector terminals) Red/Yellow to Blue/Black should enable the headlight when the key is turned on.

If that works, then you could tape the jumper wire in place and run like that... with the one drawback that you're putting extra load on your battery when it could probably use the extra current to start the engine. Or you could order a proper relay from Len.

Edit: 3rd choice is that you could also use a generic SPST automotive relay with a 1A diode added. A bit of soldering would be needed, and you'd probably need to replace the connector. Let me know if you want details on how to do that... not sure how reasonable (or unreasonable) the factory price is for the stock (probably) Nippon-Denso part.

 

Yes. (If the red wire has a yellow stripe, all the other colors correspond.)

That is your turn signal cancelling unit. Be nice to it; they're quite expensive and no longer available.

 

Picked up a used relay on eBay for $20.

Turns out having a headlight relay and fuse actually helps the headlight to work! Whoddathunk?

Thanks for the help everyone!

 

Try the diode block located in the headlight it is warped in a foam and if it is shorted of melted you can not see until you pull it off. Its worth a try but a very hard part to track down

 

Thank you yes i do believe it was the head light relay that caused me to make this post i used a jumping technique that made the head light function