Author Topic: Park light always on. Even when key is removed.  (Read 607 times)

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Offline bullfinch

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Park light always on. Even when key is removed.
« on: May 21, 2024, 02:33:44 PM »
Vin CB7502105***

For whatever reason after fixing every other issue on my cb750 my lights have started to act up.
Its been a project since forever with an engine rebuild etc.

The other day suddenly my park light was always on.
I had a fuel cock that leaked 10 liters of fuel everywhere even though it was off for 3 weeks. I replaced the fuel cock, removed fuel from the air filter box and refitted it. I might have touched some cables when working with the air box. This is why I mention it.

I checked the wiring diagram and haynes claim both french and german sohc have a brown wire that goes to the ignition switch and to the park lights. Therefore I was thinking the ignition switch was the problem. I took apart the ignition switch two hours ago and someone has done their part modifying it. Even when its completely apart the park light is stil on. I have some electrical skills, but as the ignition switch has been spliced into the wiring harnes im not able to disconnect the wires from eachother without cutting wires and futher molesting the harness. Right now im looking for reasons to why this has suddenly happened, further steps to diagnose the problem or which wire to cut in the modded ignition switch if any.

The brown and red wire in the back are soldered together and they are 12v/hot. Im considering desodering a wire in order to try to locate what is going to the front and rear park light.

Should I start to cut a wire or any other steps i should take?

« Last Edit: May 21, 2024, 10:40:01 PM by bullfinch »

Offline bryanj

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Re: Park light always on. Even when key is removed.
« Reply #1 on: May 21, 2024, 02:52:33 PM »
Get a new, correct switch
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline scottly

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Re: Park light always on. Even when key is removed.
« Reply #2 on: May 21, 2024, 08:02:47 PM »
When the key switch is in the P (park) position, the red wire is connected (sodered??) to the taillight brown wire, and the key can be removed. With the key in the off position, there should be no connection between the red and brown wires, and the key can also be removed.
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Offline bullfinch

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Re: Park light always on. Even when key is removed.
« Reply #3 on: May 21, 2024, 10:43:08 PM »
Soldered, sorry.
I changed it in my text.

Thanks for your tips. Ill try to disconnect the front park light bulb and try to locate which wire it is getting power from.

Offline willbird

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Re: Park light always on. Even when key is removed.
« Reply #4 on: May 22, 2024, 04:11:48 AM »
Vin CB7502105***



I checked the wiring diagram and haynes claim both french and german sohc have a brown wire that goes to the ignition switch and to the park lights.

On my K2 there is a brown wire in the headlight shell that is not used, my understanding is that Euro bikes were required to have an illuminated side marker light that the brown wire was used for in those markets.

Bill

Offline Deltarider

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Re: Park light always on. Even when key is removed.
« Reply #5 on: May 22, 2024, 07:58:07 AM »
Vin CB7502105***



I checked the wiring diagram and haynes claim both french and german sohc have a brown wire that goes to the ignition switch and to the park lights.

On my K2 there is a brown wire in the headlight shell that is not used, my understanding is that Euro bikes were required to have an illuminated side marker light that the brown wire was used for in those markets.

Bill
Not a side marker light, but a small Ba9s bulb in the headlight reflector, a pilot light also known as city light which is also a parklight.
CB500K2-ED Excel black
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Offline willbird

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Re: Park light always on. Even when key is removed.
« Reply #6 on: May 22, 2024, 08:51:26 AM »
Vin CB7502105***



I checked the wiring diagram and haynes claim both french and german sohc have a brown wire that goes to the ignition switch and to the park lights.

On my K2 there is a brown wire in the headlight shell that is not used, my understanding is that Euro bikes were required to have an illuminated side marker light that the brown wire was used for in those markets.

Bill
Not a side marker light, but a small Ba9s bulb in the headlight reflector, a pilot light also known as city light which is also a parklight.

Interesting :-). I have seen a few reflectors that had the socket for a small bulb like you decribe.

Offline bryanj

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Re: Park light always on. Even when key is removed.
« Reply #7 on: May 22, 2024, 09:21:15 AM »
In the UK we have an increfibly large book called"  Construction and Use Regulation for Motor Vehicles" which has evolved over many decades, talks utter government crap and regularly contradicts itself but in there a motor vehicle with lights must have "obgliatory lights" which is the small front light and 5 watt rear light.
Aparently headlamps are optional but if fitted must work and have a dip that does not dazzle .
Just more useless info for you all
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline scottly

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Re: Park light always on. Even when key is removed.
« Reply #8 on: May 22, 2024, 09:55:31 AM »

The other day suddenly my park light was always on.

If the problem suddenly started, what changed?
Don't fix it if it ain't broke!
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Offline bullfinch

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Re: Park light always on. Even when key is removed.
« Reply #9 on: May 22, 2024, 11:56:39 AM »
Lately i fixed the leaking fuel cock and removed and replaced the air filter since the fuel leak left some fuel in the air filter box. I have now desoldered the wires from the ignition switch and unplugged the wires to the park lamps. If i plug the wires in they still light up. So the ignition switch seems to have nothing to do with it.

Trying to trace the wires for the park lights right now.

Offline willbird

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Re: Park light always on. Even when key is removed.
« Reply #10 on: May 22, 2024, 12:32:09 PM »
In the UK we have an increfibly large book called"  Construction and Use Regulation for Motor Vehicles" which has evolved over many decades, talks utter government crap and regularly contradicts itself but in there a motor vehicle with lights must have "obgliatory lights" which is the small front light and 5 watt rear light.
Aparently headlamps are optional but if fitted must work and have a dip that does not dazzle .
Just more useless info for you all

It could be worse, they could require the port and starboard lights used on boats so one can easily tell if you are coming or going :-).
https://aceboater.com/navigation-lights



Offline bullfinch

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Re: Park light always on. Even when key is removed.
« Reply #11 on: May 22, 2024, 12:50:07 PM »
I found the short circuit. Making a new wire now, cleaning the switch while I'm at it.

Thanks for the support!

The red and brown wire from the original wire loom has a short on its way to the ignition switch.

I'm very happy that I was able to figure this out.

Offline bullfinch

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Re: Park light always on. Even when key is removed.
« Reply #12 on: May 22, 2024, 01:59:01 PM »
Photo of the problem cable.

Offline bryanj

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Re: Park light always on. Even when key is removed.
« Reply #13 on: May 22, 2024, 11:28:58 PM »
The butt splices higher up suggest its been played with
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Online Don R

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Re: Park light always on. Even when key is removed.
« Reply #14 on: May 25, 2024, 07:51:41 PM »
 It probably once had the key switch relocated up to the light panel/top tree area. I'm a big fan of the vintage connections Honda 3.5mm bullet connector kit and crimper. I've been able to make a lot of modified wiring appear original again.
 I accidentally ordered 4mm bullet connectors once and they come in handy on my Suzuki, the Kawasaki I sold and race car.
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