Instrument light wiring

[Littleeagle28]

Just joined.  Have a cb400f2. Instrument lights not working from PO. Removed them, no bulbs fitted, so replaced, still no joy. Removed headlamp and removed wires to brown/white connector and tested for feed after turning on ignition and headlamp switch to on, no joy.

Is there a continuity test I can do from the brown/white wires, or other suggestions?
Arnie

[LesterPiglet]

Not sure about the fuse arrangement on the 400, but have you checked them? A look isn't enough as these can fail and still look okay.

[Littleeagle28]

Hi Lester
All fuses ok, used a multimeter.

[Lobo]

Hi Arnie,

Assume you've also checked the green earth feed wire is 'good', ie have you tested continuity of the bulb holder directly to the -ve terminal of the battery?

(2) the bullet connectors can get a bit loose if taken apart too often. (& on a 37 yr old bike they will have been)

(3) underneath the tank, forward frame, LHS is a 'boot' where many loom connections (including the ones you're having trouble with) are made. Double check all tight here.

(4) If still no joy try connecting the Brown / White lead into the White (Low beam) feed instead, or Blue (Hi beam) feed... just to help you with the trouble shooting.

(5) Don't have the UK wiring diagram in me, but you could, of course, wire the Brown / White directly into the small 'parking lamp'.... only issue here is that your instruments would be permanently illuminated when lights left on in Key position 'Park'

(6) if still no luck perhaps this part of the loom has failed about the steering head. I assume you've already checked for continuity between the tank 'boot' & the actual bulb holders?

Good luck...
Simon

[Littleeagle28]

Thanks Simon

1/2.  Green earth is all good, and I also attached feed direct from battery to instrument cluster through the brown white connector and all lit up ok.

3.  Have taken tank off and inspected rubber boot connectors and reconnected. Everything ok except brown /blue wire from headlamp switch which had no female connectors to connect to in loom, so ended up connecting to black loom connector instead (this appears to be in some wiring diagrammes I have.

4.  Works ok when fed from battery +ve.

5.  Have thought of this, and may have to end up doing it anyway.  I always ride with lights on so should be ok.

6.  This is where the wiring diagramme confuses me as there is no brown white wire in the boot, as I believe it is connected within the loom where I can't get at it.

Thanks for all your ideas, appreciated
Arnie

[Lobo]

Hi again Arnie,

You sound well upto speed with your own electrical trouble shooting.

Does the tail light work OK, both in Ignition position #2 (PARK) and also normally at handle bar lights switch on?

Simon

[Littleeagle28]

Hi again Arnie,

You sound well upto speed with your own electrical trouble shooting.

Does the tail light work OK, both in Ignition position #2 (PARK) and also normally at handle bar lights switch on?

Simon

Have now located open circuit between black wire In headlamp s/w . P h, so have dismantled rhs s/w and have the joyous task of repairing it.

..and all because I wanted the instrument back lights to work, I don't even intend to ride at night if poss, yuk!