Rear light issue!

Hello!

Last week I bought a Xj750 seca-82 (uk-model) similar to the one I owned in my youth.

This one runs as great as my former one but the rear light; plate-light and foglight wont work. Brake light; headlight; turn signals and panel-light works fine.

Today I sorted out the cables in the headlight-housing and checked them with multimeter. On the connector thats attached to the ignition switch I get good voltage from the brown and red lines (lower connections) but no power seems to pass through to the red/blue cable and further to the 5A-fuse.

I would be very thankful for advice here; could it be malfunction in the ignition switch or is the connector poor?

Best regards from Sweden!

 

Congratulations on getting another, trace the wires from the tail light and make sure they are connected into the wiring harnesss.

 

Thank you!

 

Congrats on getting the XJ....

Yes tracing the wires out from the rear lights, under or along side the seat and find the connectors. Make sure they are in the correct places and well seated in the connectors. cleaning them might help too. Guessing something came lose or got unplugged along the way.

 

I am looking at the Haynes manual for the UK model and you have a switch to disable that circuit and it has three positions - Off, PO, and On; make sure it is in the correct position and try PO and On. The tail and license lights should illuminate in either the PO or On position when the key is switched to ON

{{{Side note looks like an error on the wiring diagram for the lighting switch head light control in the Haynes manual }}}

With the lighting switch set to either PO or On and ignition switch set to On check the input to the ignition switch, the blue wire. This is the output of the "lighting switch" and there should be 12V on the blue wire. If you have the 12V there and not on the L/R wire (the output of the ignition switch) then yes time to start looking at the ignition switch.

If you don't have 12V on the blue wire input to the ignition switch then either the "lighting switch" is bad, or it's not getting its input from the R/Y wire that comes from the fuse box

The gauge meter lights are a good check too, if they are illuminated then the lighting switch is working and you should have 12V to the ignition switch at the blue wire

 

Great; I will continue work today!
The gauge meter lights works fine so my next step would be to make a test shortcut from red cable to blue/red. If the taillight wakes up by then I guess the next step is to clean up the ignition lock.

I’ll be back!

 

That will bypass the ignition switch, but make sure the L (blue) input 12V is there to the ignition switch to verify the wiring is OK. I would suggest shorting from blue to blue/red and see if taillight illuminates

This is for the 650, but may help if you need to go inside your switch

https://www.xj4ever.com/clean and lube the ignition switch.pdf

 

So that bike had a "black out" feature from the factory....forward thinking...lol

 

One step further!

Today I made a careful bypass/bridge between red cable and red/blue cable. Foglight and taillight worked fine!

Nice to know that the wiring rearwards seem to work ok. Next step was to remove the ignition lock to clean it and there was a new surprise; the lock unit was litteraly broken into pieces!

Of course there could be other failures but I’ll start to get hold of a new (or better) ignition lock