Honda Cb 750 tail light wiring question

[78cb750-2]

Tail light question... The first photo is the rear of my old tail light off a 1978 Honda CB 750. There are 3 wires going from the bike to this light indicated by the 3 red circles. The second photo is the new light I purchased which has a housing that it gets bolted onto (not pictured here). This light has only 2 wires coming from it. My questions is what wires do I connect to which? I though that the center connector on the old light was a ground but it blows the fuse when I ground it. Does anyone have any help to offer, speak simple because I'm borderline retarded when it comes to this stuff. Or perhaps there is a sit where I can go that explains how to hook this up without killing myself. Thanks in advance.

[ratrodbobber]

hey 78cb i feel your pain. but i have a similar light hook up on my 80 cb750 and im thinking that the two bolts on either side are grounds cause i had the same problem the red is running light which i spliced to orange and i used the black wire as the brake light which i spliced into green on the stock wiring harness however our harnesses could be different cause of the two ear difference but i doubt it. see if this works if not i'll see if i can help in any other way.


-ratrodder

[78cb750-2]

Someone told me you just have to run a ground wire from the bolt on the light to the Green on your harness under the seat and the brake and tail light both work. I'm going to see if this is as "plug and play" as it sounds tonight.

Thanks man!

[brcree]

 Here ya go, Your old light housing was rubber mounted to the light bracket, it needed a ground wire.  Your new light housing will ground itself to the mount bracket when you bolt it on. Just hook up the two wires from the new light to the colored wires. Don't use the green one, that was the old ground wire. Hope this helps...................

[bear69]

You may have this sorted by now, but anyway......

In your first pic (original fitting) the brown wire is for the tail lamp, green\yellow is stop lamp. the metal tag took a green wire to earth.

On your replacement unit, the red and black do the stop & tail job, but you will have to find out which does what. You may need to bolt the green wire to it if the housing is not grounded to the frame.

If it is blowing fuses just try connecting one circuit (red or black + green earth) to test. It shouldn't blow via the earth wire. Hope this helps.