Topic: 400F Dimmer Switch Problems ?

[gregk]

I checked the old files" regarding no power to the headlights " and no answer to my problem.  There was however a post which indicated that the brown/blue wire at the junction beneath the tank was connected to a black.  I noticed this in my harness and another harness from a donor bike.  Coincidence, i think now. 
My present problem is with the headlight and or the dimmer switch.  There is no power to the headlight.  I assume that the source is from the dimmer switch.  The signals and the horn both work and I believe that they both get the power from the same wire. 
The only way I can get the headlight to work is hook up the white lead at the headlight to that mysterious brown wire in the headlight bucket, as it is hot. 
If the left hand switch has a common power source, could the circuit be broken to the dimmer switch? 

[SAMSIXER]

i beleive power comes from the starter button circuit, which is a black/red wire. check there

[gregk]

i think that the power comes from the Black/yellow wire. 

[ken736cc]

On models without an off switch for the headlight, power is also routes through a secondary switch at the starter button. I have seen a lot of these go bad, the plastic housing breaks.

[TwoTired]

The headlight gets power from the blue or white wires.
The blue and white wires get power from the Hi/Lo switch.
The Hi/Lo switch gets power from the Bk/Y wire.
The Bk/Y wire gets power from the Headlight fuse.
The headlight fuse gets power from the Bk/R wire.
The Bk/R wire gets power from the starter button switch.
The starter button switch gets power from the Black Wire when the starter button is NOT pushed.
The Black wire gets power from the Main switch.
The main switch get power from the Red wire.
The red wire gets power from the Main Fuse.
The main fuse get power via another Red wire from the battery.

The brown wire in the H/L bucket is used on a front "position" bulb for UK models.
It is fused by either the tail Fuse or the Main fuse depending on the Main switch position.

Information from the Haynes shop manual Wire diagram.  Handy those wire diagrams.

Cheers,

[gregk]

No power at the fuse.  There is power at the black going to the starter button.  Must be in the button itself.  The starter does work so power must be getting there somehow.
Will take it apart this weekend or is it a servicable piece?

Thanks for all the help.

[TwoTired]

The starter button switch itself has a couple springs and tiny balls with wanderlust.  The little plastic housing it all resides in is prone to disintegration from leaky master cylinder brake fluid.

I have been able to collect, clean, and glue all the little plastic bits togther to form a functioning starter button switch.  But, it is a tedious challenge that very few people enjoy or have success at doing.  It is a pity you can't simply buy the little switch inside the control block.  I've only found the entire control block available as a replacement part.  New ones are very pretty, though.

Cheers,

[Bodi]

There is some weirdness with the 400F, on models intended for some countries (ie USA) without an on/off switch. There are 2 wires in the cable to the (on-off switch-less) handgrip switchgear. They are different colours, black and something else - brown and a stripe IIRC, and they are just spliced together in the harness (in some countries the headlight on-off switch would connect them). SO.. if you pull on either wire, the spliced pair falls out of the sleeving. And if you get a replacement switch set that looks and works the same from some other bike, it won't have the spliced wires. Either way, unless you jumper those wires at the under-tank connection ratsnest you get no headlight power.
The Honda shop manual wiring diagram shows this exactly. Haynes and Chilton wiring diagrams leave out some interesting details.

[gregk]

I got around to checking the switch this past weekend.  i started at the fuse box and jumped power to the headlight fuse.  All worked fine, high and low beam and indicator bulb as well.  Now checked the wires at the kill/starter button.  No power comming out of the black wire.  These switches all look the same to me, at least on the outside.  My 76-750 and an early goldwing all looked teh same.  Shouldn't be a problem to get one out of the wreckers.  I believe that I shouldbe able to check the circuit of the switch.  Hopfully, problem solved. 

Thanks to all for the help, This was a leson well learned.

[bryanj]

Some switches have block connectors others individual wires

Make sure you get one with the two throttle cable holes

Make sure what you get IS NOT off a CDI ignition bike (400twin etc) as the kill switch is different

You have to be carefull on year as the opperation of the starter button changed from grounding the solenoid via the bars to powering the solenoid via the wiring

Hope that helps

[TwoTired]

I got around to checking the switch this past weekend...  Now checked the wires at the kill/starter button.  No power comming out of the black wire. 

   The black wire is power going TO the switch.  The black/red wire is the power from the switch.  The switch can't distribute power it doesn't receive!

This data does NOT condemn the switch.

[Bodi]

Here's a picture of the jumper



The switch assembly either has a headlight on/off switch connecting these wires when ON, or a jumper inserted in the switch cable sleeve if you have always-on headlights. If someone has replaced a 400F "always on" switch assembly with a generic one - same switches but no jumper - or the jumper has been removed (it pulls out easily but is a bugger to slide back into the sleeve) you have to add this jumper. The pictured one needs some insulation on the soldered joint of course!

This detail is not in the Clymer or Haynes wiring diagram.

[gregk]

Another mystery solved!  I have two wiring harnesses and both had this jumper wire inside the connector under the tank.  It appears to jump from a brown wire to the multi connector for the black wires. 
Strangely, my jumper wire is identical to that shown in the photo previously posted.  i did however, put some shrink sleeve on the splice. 
Was it Honda who was installing this jumper?  Like you said, this splice does not appear in the wiring diagrams. 
I found a switch from a 550 honda but the ends were block connectors so I had to change them to individual plug conectors.