Author Topic: Earthing Rear Indicator  (Read 6601 times)

Offline Neilw

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Earthing Rear Indicator
« on: April 30, 2026, 06:28:35 PM »
I've purchased an after market rear indicator and there is no earth. The wiring diagram shows an earth and live.

Can i attach an earth to the position next to the bulb?

Offline Oddjob

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Re: Earthing Rear Indicator
« Reply #1 on: April 30, 2026, 06:39:39 PM »
Yes, it’s where Honda attach to when they fit an earth.
« Last Edit: April 30, 2026, 09:54:46 PM by Oddjob »
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Accidents in the back seat cause kids.

Offline McCabe-Thiele (Ted)

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Re: Earthing Rear Indicator
« Reply #2 on: April 30, 2026, 09:14:40 PM »
I would attach an earth wire even though some modern lights use a conductive plastic  paint/ layer instead.

My old Vauxhall Carlton used to blow bulbs regularly, the poor contact on the reflector would make bulbs blacken after a few months. I ended up putting an earth wire on both rear lamps to fix the issue.

« Last Edit: April 30, 2026, 09:17:21 PM by McCabe-Thiele (Ted) »
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline Bryanj

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Re: Earthing Rear Indicator
« Reply #3 on: April 30, 2026, 11:23:20 PM »
The earth is actually through the casing, the mount and to frame

Offline Neilw

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Re: Earthing Rear Indicator
« Reply #4 on: May 01, 2026, 09:24:24 AM »
The earth is actually through the casing, the mount and to frame

The wiring diagram shows the earth going to a three way earth connector, which is what i was intending to attach it to. I guess eventually it grounds to the frame or engine?

Offline Bryanj

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Re: Earthing Rear Indicator
« Reply #5 on: May 01, 2026, 12:10:01 PM »
Whose wiring diagram?

Offline Oddjob

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Re: Earthing Rear Indicator
« Reply #6 on: May 01, 2026, 01:20:03 PM »
The 500 has both earth and feed Bryan. The earth is riveted to the mount on the rear and you can easily miss it being there. The 550f had them attached to the bulb mount screw, a much better system.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline Bryanj

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Re: Earthing Rear Indicator
« Reply #7 on: May 01, 2026, 03:36:55 PM »
There is only 1 wire on all the 500 rear indicators i have and 2 on the US front ones, 1 on the UK ones.
There is a short ground wire fronm the bulb holder to one of the holder mounts from memory as some bulb holders are rubber mounted.

There was a ground wire riveted to the back of the steel mounting that the head mounted to

Offline Neilw

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Re: Earthing Rear Indicator
« Reply #8 on: May 01, 2026, 04:10:20 PM »
Whose wiring diagram?

I have the 550 f2, wiring diagrams in Haynes and also Hondas.Orange and Green cables from the left and Green and Light Blue for the right.

Offline Sesman

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Re: Earthing Rear Indicator
« Reply #9 on: May 03, 2026, 08:02:24 AM »
As long as you are using the correct shouldered mounting bolt and rubber mountings the earth will be just fine through the frame. I too have used those aftermarket market indicators using the single wire/bolt ground with no problems.