Honda Twins banner
1 - 10 of 10 Posts

·
Premium Member
Joined
·
417 Posts
Discussion Starter · #1 ·
1976 CB360T

My gauge lights are all out. I do not ride much at night, so I really cannot be sure that they ever did work since I got the bike. I bought new ones and put one in to test. It did not work.

With the key off and the bulb leads disconnected from the harness, I put a ohmmeter on frame ground and Brown/White in the harness. Dead short.
With key on, I get 0 volts at the same point.

The ignition/key switch was removed, cleaned and tested. The contacts are functioning as they should be. I have disconnected it from the harness to take it out of the equation. I get the same results with it installed or not.

With the ohmmeter still grounded, I moved the other lead to the next contact point, the Brown/White connector on white plug near the fuse box. Shorted.

The Brown/White connector then goes on to taillight fuse. With the fuse in place I get a short at either side of the fuse-as you would expect. With the fuse removed I get a short on the 'other' side of the fuse holder. That is the Brown/Black wire. (It may be Brown/Blue as indicated on the diagram- it is hard to determine the stripe color).

The diagram indicates that there should be a bullet connector inline before it goes to the Right Handlebar control. I cannot find that connector.

Also, the diagram indicates a headlight control. Are they referring to a switch? My headlight shuts off on starting. I have the starter switch, and kill switch on that right side.

The left side, has the directional control, hi and low beam and horn.

I may be overlooking something simple. My thought is that somewhere in the harness I have a short on a wire that may have worn through the insulator. Or that there is something funky going on in the right hand control.

Do the controls I have seem to be consistent with a '76 360CB?
 

·
Sensei
Joined
·
27,183 Posts
Re: I have a short. I just can't seem to find it.

The yellow to white is correct....It's part of the charging circuit....However, It has to be the white that runs back the harness to the alternator connection, NOT the headlight white....
The rest I'm still sorting out, but appears you have the "wrong" r/h switch unit
 

·
Premium Member
Joined
·
417 Posts
Discussion Starter · #3 ·
Re: I have a short. I just can't seem to find it.

Update:
I found the Brown/Blue connector in the large connector nest under the gas tank. I only found the male end and it was plugged into a multiple black connector. I did not find the mate for the Brown/Blue. Can there be any good reason that was plugged into the black?

Also while I was in there, a yellow and white were connected together. I have not traced that out yet.

I am going to make all the reconnects to see if the gauges work.

Steve, I would still be interested in hearing your opinion on this because I am still not sure all is cured.

Update 2: Well it seems that the entire Brown/White circuit is fed power from the Brown/Blue wire that is plugged into the Black connector upon key turn to the first position. I think that was done as a shorcut and it seems to have bypassed a switch that my bike does not have.

I thought I had it.
 

·
Premium Member
Joined
·
417 Posts
Discussion Starter · #4 ·
Re: I have a short. I just can't seem to find it.

66Sprint said:
The yellow to white is correct....It's part of the charging circuit....However, It has to be the white that runs back the harness to the alternator connection, NOT the headlight white....
The rest I'm still sorting out, but appears you have the "wrong" r/h switch unit
Are you thinking that there should be an 'On-Off' switch on the right switch unit? (I just saw a pic of a RH control from a 72 CB750 and it looks exactly like mine except that it has the On-Off switch.) That would make sense. That would make the Brown/Blue to Black connection that is hardwired on my bike when the switch is in the on position. If that is all true and if having it hardwired does not do any damage to the bike, my next step may be to open up the harness and take a good hard look for some other short in the system. The brown/white circuit seems simple enough. This one is driving me batty.

And just for full disclosure and I did not think it was related(I still don't). The PO had plugged the starter push-button switch on the RH control with a rubber stopper and mounted a starter switch on one of the handlebar bolts in the center of the steering column.
 

·
Sensei
Joined
·
27,183 Posts
Re: I have a short. I just can't seem to find it.

That IS actually connected (sorry about the pun) to your problem... On your bike, the lighting power originates when the ignition is turned on....The taillight gets power through the fuse (brown/white) and the headlight gets power from a black wire leading to the starter button.... When you depress the button, it diverts this power from the headight and sends it to the solenoid (light goes out) once you release the button, it reconnects the power to the headlight.... We may need to do an evening phone call to track the exact problem while you can be at the bike.....
 

·
Premium Member
Joined
·
417 Posts
Discussion Starter · #6 ·
Re: I have a short. I just can't seem to find it.

66Sprint said:
That IS actually connected (sorry about the pun) to your problem... On your bike, the lighting power originates when the ignition is turned on....The taillight gets power through the fuse (brown/white) and the headlight gets power from a black wire leading to the starter button.... When you depress the button, it diverts this power from the headight and sends it to the solenoid (light goes out) once you release the button, it reconnects the power to the headlight.... We may need to do an evening phone call to track the exact problem while you can be at the bike.....
You're only about 3 hours away. Take a ride down #81 and #77. :D

The switch is not a momentary switch. It has two positions(double throw). The bad thing about that is that it can be left in the on position and the starter will crank and crank.
The switch does what it is supposed to as far as the headlight goes. When moved to the start position the headlight goes off and the bike starts. When the switch is moved back the lights come back on. I would really appreciate a call to sort this out. I will get some good close up pics and descriptions so you can 'see' what I am looking at while we talk. I will send you a pm to get an email address so I can send you my info and the pictures. Thank you so much for the offer.
jon
 

·
Sensei
Joined
·
27,183 Posts
Re: I have a short. I just can't seem to find it.

No PM necessary... I post it all the time..... 540-427-4256 is my land line.... Call 540-525-5199 (cell) to tell me to shut down the computer (dial-up)....
 

·
Premium Member
Joined
·
771 Posts
Re: I have a short. I just can't seem to find it.

Hmmm......

Red is battery.
Red connects to black when ignition key is turned on.
Black connects to Brown/bluestripe when headlight switch (on right handlebar control) is turned on.
**EDIT** Just discovered I was looking at a non-1976 wiring diagram. The 1976 diagram shows that the Brown/bluestripe is hard-connected to Black. So, Black connects to Brown/bluestripe always.
Brown/bluestrip supplies taillight fuse.
Fuse supplies Brown/whitestripe.
Brown/whitestripe supplies speedo and tach bulbs AND goes to second set of contacts in ignition key.
Second set of contacts in ingition key connects Brown/whitestripe to Brown when ingition key is turned on.
Brown supplies taillight AND 'empty' connector (for customer's use).

So, how can Brown/whitestripe be shorted to ground and yet somehow the Brown taillight wire is still getting supplied thru the key switch? (Because your taillight is still working correctly).

How can Brown/whitestripe be dead shorted to ground and NOT blow the taillight fuse?

Something simple being overlooked here, it seems to me...
 

·
Premium Member
Joined
·
417 Posts
Discussion Starter · #9 ·
Re: I have a short. I just can't seem to find it.

kirkn said:
Hmmm......

Red is battery.
Red connects to black when ignition key is turned on.
Black connects to Brown/bluestripe when headlight switch (on right handlebar control) is turned on.
**EDIT** Just discovered I was looking at a non-1976 wiring diagram. The 1976 diagram shows that the Brown/bluestripe is hard-connected to Black. So, Black connects to Brown/bluestripe always.
Brown/bluestrip supplies taillight fuse.
Fuse supplies Brown/whitestripe.
Brown/whitestripe supplies speedo and tach bulbs AND goes to second set of contacts in ignition key.
Second set of contacts in ingition key connects Brown/whitestripe to Brown when ingition key is turned on.
Brown supplies taillight AND 'empty' connector (for customer's use).

So, how can Brown/whitestripe be shorted to ground and yet somehow the Brown taillight wire is still getting supplied thru the key switch? (Because your taillight is still working correctly).

How can Brown/whitestripe be dead shorted to ground and NOT blow the taillight fuse?

Something simple being overlooked here, it seems to me...
Well, the problem is resolved but I am not necessarily satisfied.

I read this at work with a copy of the wiring diagram (by the way where did you get yours? I cannot find one that indicates a hardwired Brown/Blue to Black). Of course everything you state make sense and that is what has been so frustrating. I think that the 'short' to black with the power off is normal. I did not really understand that part of it. So I was going by the assumtion that I had a short. When power was applied with the key turn, the expectation at Brown/white is 12v. When I got 0v I assumed that my short theory was correct. What I should have been looking for is an open in that Brown/white circuit somewhere. Now the part that really kills me is that as I started testing everything tonight, it all looked correct. I plugged in the gauge light leads and I am getting 12v. I put in a bulb and it lit right up. I buttoned up and tucked in all of the connectors with the key on and a guage light in. Every wire got a good shake to see if I could get the light to flicker. After the seat and gas tank were back on, I again tested all functionality and all is working.

I have no idea what the cause of the this whole fiasco was. And, of course, it will rear it's ugly head again one of these days.
Thanks to all that responded.
jon
 

·
Premium Member
Joined
·
771 Posts
Hey! Glad to hear it works! But you're right - If YOU didn't fix it, then you probably didn't FIX it... I hate issues like that. :D

I'm going with a bad connector theory. Wiggly-jiggled, disconnected-reconnected and now it works. Hmmm.....

I got my non-76 diagram from the Factory Shop Manual that's linked here and there on this site. I've scanned the diagram as a jpeg and have been using 'Paint' to colorize it appropriately. The '76 version was posted in another thread somewhere here in this forum too. I just saved it to my computer and was looking thru it. The '76 has a handful of little changes from earlier - the '76 doesn't have the lights shut-off switch anymore on the right handlebar (according to the diagram anyway); the '76 headlight gets it's power via the electric start button so that pushing the e-start actually shuts off the headlight momentarily; the '76 has a switch on the clutch lever to prevent starting in gear if the clutch isn't pulled in; the '76's taillight/dash lights are powered up anytime the key is switched on. And maybe a few others I'm missing.

Still, glad to hear it's working. :)

Kirk
 
1 - 10 of 10 Posts
Top