Topic: Front signal and dash lights backwards

[drumstyx]

Just roughing in the electrics, and wanted to test it out with my battery charger set to 15A. Seems to work alright, except that for some reason, the front signals are completely backwards. The rears are correct.

I've confirmed that the lights installed on the right side are blue wired, and lights on the left are orange wired, for all signals and dash lights. I figure that since the rears work correctly, it can't be the switch being backward. All colours line up on the plugs. The harness is brand new (could it be something screwy there?)

I just tried doing some rudimentary testing on the harness, and found continuity (with varying resistance) between all 4 orange/blue wires at the front and back (see edit)...confused!

Bike is a '78 CB750K.

EDIT: No cross-continuity in the harness, I unplugged all the lights and it tested good -- must have gotten continuity through the bulbs.

[el pachuco]

just switch the front, left and right blinker wires into the harness. Ignore the color matching.

[drumstyx]

That gets the job done, but honestly it's boggling my mind. I've taken all connections back apart and checked the harness, blues only connect to blues, and there should be no possible way for this to happen.

Amidst all this, I burned a fuse and killed a flasher, driving me madder (protip, don't try to do anything with some things unplugged unless you're sure the exposed conductors won't be +ve ever)

[b52bombardier1]

+1 on ignoring the color. The only thing I'd suggest is tagging the wires with what you are switching so that some future owner will know what you did. Or clip some wire of the proper color and stripe off an old wiring harness and make it right.

Rick

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[drumstyx]

The plot thickens.

I didn't have the frame ground under the tank attached, as I found there was ~3 ohms of resistance between ground and ground wires already -- attaching the frame ground has reduced that well under 1ohm.

After attaching the frame ground:

The dash signal lights are now correct, but front signal lights are not. Also, the taillight flashes with the signal lights...is this supposed to happen? When holding the switch only slightly, as if changing lanes, the front lights don't work, and the dash lights are again backwards -- what a wonky machine!

[eigenvector]

Nothing wonky about it.  You just have a bad ground somewhere.

See this a lot in trailer wiring - ground contact breaks and suddenly everything wants to flash with the turn signals.  I'd look at the front signals and how good their ground is.

[drumstyx]

Ok, fair point, I fixed the ground to the fronts and now they *both* flash -- the running lights appear to also be flashing, opposite to the correct one (or maybe both running light filaments are going...can't really see with the bright flashing)

Also, the gauge backlights (brown/white) flash with the signals, and that's measured at the harness, which seems to have a solid ground...

Where are the important frame grounds? Of note is also that I don't have a battery -- the positive of the charger is connected to the starter solenoid (where the positive wire for the harness is), and the main ground is near the coils (which aren't in place) mounted to the frame, and where I clamp the negative. Engine is not in place, nor is any of the charging system. Is any of that required for things to work correctly?

[martin99]

Are you sure you've got your wiring right? Maybe connected a blue (lights) to a light blue (signals) somewhere? Aftermarket harnesses aren't always exactly true to original colours, so easy mistake to make.

[drumstyx]

I think I've figured it out somewhat...the colour brown/blue-stripe is reused once in the harness -- the turn signal beeper (which I don't have, or intend to have, and is obviously switched with the signals) and the running lights (dash backlighting, taillight, front signal secondary lights). In the bucket, I had these connected, as the colours and connectors match up, but according to the diagram brown/blue-stripe in the harness connects to black (ignition). I tested this with a jumper and it worked great. Problem is, both brown/blue-stripe and black are female...

[drumstyx]

Never mind -- looks like there's a jumper wire that goes between them that I'd forgotten in the original harness. Seems to not be OEM connectors on it, but it all works now