Author Topic: Wiring problem... Little help? - MADE some progress! (Read 1252 times)

Stogie1020 · « **on:** July 31, 2010, 07:36:43 PM »

I will admit, I have NO idea how to read a wiring diagram. There I said it.

Got the 78 CB750 from PO with both rear flashers removed. Front didn't work but were attached.

I want to get them all up and running.

I opened the headlight bucket and traced the front running lights/flashers and found that both wires from one were going to hot leads and both wires from the other were going to ground connectors.

Is this right? Shouldn't it be one wire from each going to hot and one from each going to ground? Are there specific connectors the running lights/flashers are supposed to connect to so the left hand switch activates them?

Also, can the fronts work without the rears installed?

I have been studying the wiring diagrams for the bike and the longer I look, the less sense they make...

scottly · « **Reply #1 on:** July 31, 2010, 07:54:08 PM »

The short story is like colored wires plug together. Pay attention to the colored stripes, or tracers, on the wires. They mean something.

TwoTired · « **Reply #2 on:** July 31, 2010, 07:55:59 PM »

The stock front signals had three connections each side, Lt. Blue, Lt Blue/Wht and green for one side and Orange, Org/wht, and Green for the other side.
The White tracer wires were front running lights and the greens are common or battery NEG terminal. The other solid colors were for the brighter blinking flashers.

The rear was the same except there are no running lights so there are no white tracer wires.

The stock flasher needs both front and rear to flash and it is voltage sensitive so a non- running bike may not flash them.

You can buy flasher units the don't care about the voltage and will flash whenever powered.

Cheers,

Spanner 1 · « **Reply #3 on:** July 31, 2010, 08:02:07 PM »

Yes and Yes.... your K8 has both running lights in the turn signals (t/s) and a second filiment for the flashing t/s
Do you have a meter or testlight?

Stogie1020 · « **Reply #4 on:** July 31, 2010, 08:06:31 PM »

Thanks guys.
I have a MM and all bulbs are good.

I look at the current replacement lights for front/rear and the fronts are two wire and the rears are single wire.

I will re-do the connections on the fronts so they to the correct places, but there are only two wires.

TwoTired · « **Reply #5 on:** July 31, 2010, 08:21:39 PM »

Then the front replacements are not stock. Should work if you just don't use the Wht tracer wires. You don't get front running lights, though.

Cheers,

Spanner 1 · « **Reply #6 on:** July 31, 2010, 08:22:26 PM »

2 wires into each signal is correct... each signal stem gets it's ground via the ground wire (green ) on the 'ring' under the stem mounting nut, so yes, there are 3 wires involved for each side...... ( front only )........ are the bulbs 2 filiment and has each base got 2 wires to it?

Stogie1020 · « **Reply #7 on:** July 31, 2010, 08:23:41 PM »

OK, I just checked and all four wires ARE actually connected to where they should be. Not sure what the ground situation is for the light assemblies, though.

Stogie1020 · « **Reply #8 on:** July 31, 2010, 08:24:45 PM »

I will check the grounds and make sure there is good contact.

Will the fronts work (even just as flashers) even if the rears are off?

Spanner 1 · « **Reply #9 on:** July 31, 2010, 08:26:17 PM »

Not as flashers, but should be always on with ignition as running lights.

Stogie1020 · « **Reply #10 on:** July 31, 2010, 08:28:06 PM »

OK, then there is either something wrong with the grounding situation or the flasher relay, as both bulbls are good, but I get one running light, sometimes and no flashers (expected if no rears).

Spanner 1 · « **Reply #11 on:** July 31, 2010, 08:37:13 PM »

Spray the lefthand switch with contact cleaner ( or WD if you have to ) and 'work it ' x20 times ( ign. off)... Try again.

Stogie1020 · « **Reply #12 on:** July 31, 2010, 08:53:42 PM »

Will do.

I connected the rears and when the key is turned, no running lights anywhere. When the indicator switch is moved, I get a solid rear for whichever side I move the switch to. Nothing from the fronts for running lights or any response to the switch being moved. I checked the front bulbs and they are OK, and I cleaned the inside of the front flasher assemblies where they mounts to the tube on the fork to ensure connectivity for the ground with a little steel wool. Grrr.

Stogie1020 · « **Reply #13 on:** July 31, 2010, 09:54:14 PM »

OK, I am ready to hurt kittens...

Got the rears working as flashers (yay!) and mounted along with the grab bar.

The fronts, though...

I sprayed the hand switch with wd40 and worked it 20 or so times.

I opened each front flasher housing, checked the bulbs on an MM and for both connection points I showed 0 ohms resistance (well ok, a minute reading, but not "blown"). I scrubbed the contact points inside the bulb socket and the ground wire connector on the socket with steel wool, and remounted the flasher units. I then unplugged each of the four connector wires in the headlight bucket and re-seated them making sure they were in the proper color coded receptacle.

Turn key to "fire rockets" and I get no running lights. I flip the flasher switch and the rears snap to attention and start winking at me like they know some secret I don't.

The fronts, though remained tight lipped and wouldn't even flicker to convince me I was hallucinating...

Grrrrrrrrr......

Stogie1020 · « **Reply #14 on:** July 31, 2010, 09:55:28 PM »

I should add that it's about 100 degrees in my garage right now. At 9:30PM. And I found a tarantula in there a few weeks ago.

Spanner 1 · « **Reply #15 on:** July 31, 2010, 10:15:33 PM »

If the rears work and the fronts not, then bad ground would be my guess if the wiring is correct...... go thru' it again, wiggle in the headlight bucket with the turnsignal switch on L or R....
+1 on the HEAT, it's unrelenting and miserable to have to work on yer bike....

Stogie1020 · « **Reply #16 on:** July 31, 2010, 11:04:13 PM »

Will do. May have to wait until tomorrow. My beer to productivity ratio has shifted...

TwoTired · « **Reply #17 on:** July 31, 2010, 11:55:14 PM »

If your front signals are not stock and have the same number of wires as the rear you may not be able to have front running lights. Can you verify the bulb numbers for the front or that they have two filaments inside the glass?

Stogie1020 · « **Reply #18 on:** July 31, 2010, 11:58:54 PM »

Definitely have two filaments, and both are intact.

I don't get ANY response from the fronts, running light OR flashers.

Rears activate as flashers only.

TwoTired · « **Reply #19 on:** August 01, 2010, 12:13:39 AM »

The front fork covers do not make a good ground, as they are rubber isolated to the forks. The bulb socket base must have a conduction path to the green wires in the wire harness. There are usually headlight mount nuts with tabs inside the headlight shell to provide this electrical connection.

Cheers,

Stogie1020 · « **Reply #20 on:** August 01, 2010, 12:35:39 AM »

The jury rigging will commence!

This is what the bailing wire is for, right?

TwoTired · « **Reply #21 on:** August 01, 2010, 09:40:25 AM »

The stock socket bases make contact with the signal stalks, and the signal stalks make contact with the upper fork covers. The headlight bolt reaches into the headlight bucket and there is a tabbed washer behind the mounting nut. That tabbed washer has a green wire connected to it, which attaches to the main wire harness green wire distribution.
This is NOT a jury rig, that's how it came from the factory.
If you don't have such a connection, what you are doing is a repair.

Cheers,

Stogie1020 · « **Reply #22 on:** August 01, 2010, 09:47:46 AM »

Then let the "repair" (I feel so official!) commence!

Thanks for the info!

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Author Topic: Wiring problem... Little help? - MADE some progress! (Read 1252 times)