brake light always on....well it seems that way

Hmmmm..... sounds like a new (to me at least) and interesting problem with the ignition safety circuit.

 

It is interesting, I'd love for a few more XJ owners to try this experiment
1. insert key and leave in the OFF position
2. put the bike in Neutral
3. step on the rear brake, then pull the front brake hard. Continue to keep both brakes fully engaged
.......what happens? For me the neutral light comes on, the taillight (and brakelights) come on, I can sound horn and switch on blinkers (the headlight stays off however). Let go of either brake at any time and the system goes dead.

other than this one odd behavior I have no electrical issues on the bike....everything works as it should
wonder if chacal has ever ran into anything like this.....

 

. looking at wiring diagram it looks like your getting voltage from the voltage regulator brown wire via battery and main fuse,
can not explain tail light

 

Specifics matter here, the tail light is not the brake light. Please pull just the front brake (hard as you suggested earlier) and see if the brake light illuminates with the key off.

My best guess is still this:

If the front brake switch is connected improperly (to a hot wire), which looks to be available per the Haynes manual as a red bullet connector then the symptoms would occur. That is, when the front brake is applied the brake light will illuminate with the key off. Then, if the rear brake switch is closed power is routed through the signal fuse to power the remaining circuits.

Also curious as to this statement. Does the key have to be in for the anomaly to occur?

 

Absolutely nothing at all happens if you just pull the front brake with the key off in neutral. Both brakes must be engaged for the brakelight, neutral light etc to come on. I never would have discovered this anomaly if my rear brake switch hadn't been stuck closed (because I never get on my bike with the key off and engage both brakes while in neutral). I do however periodically push-walk the bike around my garage and apply the front brake. Now with the rear brake switch stuck closed, this is exactly how I discovered this behavior.

I'll check the wiring from the front brake switch - it's certainly possible somewhere along the line over the past 36 years somebody connected something incorrectly (especially where wiring is concerned)

The key can be in or out as long as it's in off

 

Thanks for clarifying that.

I suspect that blows the theory of the front brake switch being wired to a hot wire, but visualizing a miswire can be difficult so since it is an easy check it would still be worthwhile. And while you are there do a good visual on the other connectors with potential to miswire (mostly bullet connectors) to verify matching wiring color codes.

Living with the anomaly is likely OK. However, depending on just what is causing it there could be a slight potential that a portion of the electrical system is not properly fused.

 

hook a volt meter to the key and see if it goes hot when this happens.
you could be getting some sort of short from park position and off. park runs the tail light.
your voltage rectifier may be developing an issue

I tried you issue on my bikes did not get your results.

 

i did put a new fuse box in, maybe I muffed something up. I'll do all of those suggestions and report. It's not causing any running issues but it would be nice to know what's causing it

 

It would have to be a huge mistake to cause this issue. I doubt that it was you.

 

.....every light, and I mean every light, got twice as bright when I replaced the fuse box.
I was thinking of converting to LED until I put this new box from Chacal and decided I didn't need to
......very worthwhile to do this as many people have already stated

 

Why do you have your accessory circuit fed that way? It should be fed either straight from the battery, or from the main after the main fuse.
It will work fine so long as it's fed from the right end of the circuit and the current draw is low enough, but it's not the best practice.
You should also have a dummy connector on the output pin for the unused curcuit, or have it disconnected entirely.

 

there are two reasons I didn't want to run my aux straight to the battery. The first is that I wanted the fuse protection and already had the space available in fuse box (so no inline fuse required), secondly I wanted my aux power switched to the key so that if I left something plugged into the cigarette adapter I wouldn't drain my battery. I really only want to be charging my phone (or whatever) while the bike is running.

All I did was pigtail into the large gauge brown (which is the main feed from the harness) to power the other two unused fuse positions. I don't see an issue with this ?

I agree on properly terminating the unused circuit with a dummy connector.

 

The main feed is the largest gauge red wire. It runs throught the ignition switch and then feeds the rest of the circuits.
The brown wire is for the signals.

 

your right, I don't know how I mixed that up......do you think this is worth changing ? I
only have a 4 amp fuse in my aux circuit and the signals run through the main switch anyway.
trying to get my head around if there is a downside to the way I did it

 

The only real downside is for later troubleshooting, either by you or a future owner.
The original harness signal wire should be fine for the potential 14 amps that it could see since it's the same gauge as the main (IIRC).

 

If you want to use switched power I would say you have it right. That is assuming the rear of the bike is the output of the ignition switch and the input to the fuse box. I doubt Yamaha had a lot of consistency on this, but on my 750 Seca the front was the output of the ignition switch and the input to the fuse box.

In the upgraded fuse box the picture resolution is not that great, but it looks like the main and signal lines were reduced in gauge - most notable on the main.

Did you find the opportunity to check inside the head light bucket to verify the correct coloring on the front brake switch?

 

front brake switch is correct, however I think it's my ignition switch. Park doesn't work at all. when in park mode can you activate the brake light and blinkers and horn ?

 

No. You should only have instrument lights and tail light on U.S. spec XJs.

 

Well things seem to just get weirder day by day. While in "P" do you have to engage the front and rear brake as with the other issue? Does the horn work independently in "P"?

So strange, I wouldn't necessarily blame the ignition switch just yet as it is too easy to check with a meter.

Disconnect ignition switch and check:

Key set to "ON" continuity from R wire to Br and L wire
Key set to "P" continuity from R to L only

Pull the 5 fuses check main harness ignition switch mating connector R to Br R to L and Br to L