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Brake light failure warning switch
Moderators: chrisu, paul doran, Taffus, KeithZ1R
Brake light failure warning switch
Hi All,
Are there any viable replacement options for the brake light failure warning switch?
Regards.
Are there any viable replacement options for the brake light failure warning switch?
Regards.
Re: Brake light failure warning switch
Not sure what bike you have but spotted this on the infamous ebay
https://www.ebay.co.uk/itm/144466604593 ... Swst9hwJWt
https://www.ebay.co.uk/itm/144466604593 ... Swst9hwJWt
010
- warren3200gt
- Hardcore
- Posts: 3049
- Joined: 13th Jun 2014
- Location: Dartford Kent
Re: Brake light failure warning switch
Assuming that ebay one works that's cheap.
PUM 488 June 2026
76 Z900A4, 77 Z650B1, 77 KZ650B1, 77 Z1000A1, 82 Z1000J2, ZRX1100R.
76 Z900A4, 77 Z650B1, 77 KZ650B1, 77 Z1000A1, 82 Z1000J2, ZRX1100R.
Re: Brake light failure warning switch
Yes correct one, but used.
CB125 GT380 CB750F1 Z1R GPZ 750 Turbo Z1R
Re: Brake light failure warning switch
r3sc wrote:Hi All,
Are there any viable replacement options for the brake light failure warning switch?
Regards.
I bought a couple of NOS KZ/Z400 ones for my A4 from the States for about £20 a few years ago, postage isn't cheap though (£15), but try finding them over here: https://www.ebay.co.uk/itm/175237676176 ... SwP-phVMm4
Current Bikes:
Phil Churchett's 1976 Z900 A4: PRE 2R https://www.flickr.com/photos/115740825@N05/albums/72157680116996884
1973 XL250 K0 Motosport: UKX 73L
2023 R1250 GSA
Previous Zeds: Z750B1 Twin, Z650B1, Z750E
Phil Churchett's 1976 Z900 A4: PRE 2R https://www.flickr.com/photos/115740825@N05/albums/72157680116996884
1973 XL250 K0 Motosport: UKX 73L
2023 R1250 GSA
Previous Zeds: Z750B1 Twin, Z650B1, Z750E
Re: Brake light failure warning switch
Hi Guys,
Many thanks for the input.
Andrew,
That is the exact item I need, for a Z400.
Is there any way to test my existing unit before taking the plunge with a NOS one?
Regards
Many thanks for the input.
Andrew,
That is the exact item I need, for a Z400.
Is there any way to test my existing unit before taking the plunge with a NOS one?
Regards
- warren3200gt
- Hardcore
- Posts: 3049
- Joined: 13th Jun 2014
- Location: Dartford Kent
Re: Brake light failure warning switch
Remove tail/brake bulb. Idiot light should flash.
PUM 488 June 2026
76 Z900A4, 77 Z650B1, 77 KZ650B1, 77 Z1000A1, 82 Z1000J2, ZRX1100R.
76 Z900A4, 77 Z650B1, 77 KZ650B1, 77 Z1000A1, 82 Z1000J2, ZRX1100R.
Re: Brake light failure warning switch
The trouble I have is that the red idiot light is on all the time whenever the ignition is turned on. Never flashes, never goes off??
Is there a test that can be done on the unit itself using a multi meter?
Cheers.
Is there a test that can be done on the unit itself using a multi meter?
Cheers.
- warren3200gt
- Hardcore
- Posts: 3049
- Joined: 13th Jun 2014
- Location: Dartford Kent
Re: Brake light failure warning switch
If its on all the time Where's is the idiot light earthing? Is the rear brake light on/ operating cofrectly? Could be as simple as rear brake switch needs adjusting.
What happens if you disconnect the failure unit? If you do that the idiot light will only come on when your front or rear brake is applied to complete the circuit.
If the idiot light remains on with the failure unit disconnected the the circuit must be grounding someplace.
Just another thought. Has it been fitted with an led bulb in the idiot light? That would mean it stays on constantly.
There is an easy fix by adding a resistor in parallel to the idiot light or just swop back to a standard bulb.
What happens if you disconnect the failure unit? If you do that the idiot light will only come on when your front or rear brake is applied to complete the circuit.
If the idiot light remains on with the failure unit disconnected the the circuit must be grounding someplace.
Just another thought. Has it been fitted with an led bulb in the idiot light? That would mean it stays on constantly.
There is an easy fix by adding a resistor in parallel to the idiot light or just swop back to a standard bulb.
PUM 488 June 2026
76 Z900A4, 77 Z650B1, 77 KZ650B1, 77 Z1000A1, 82 Z1000J2, ZRX1100R.
76 Z900A4, 77 Z650B1, 77 KZ650B1, 77 Z1000A1, 82 Z1000J2, ZRX1100R.
Re: Brake light failure warning switch
Z1000 workshop manual page 211 shows you the test procedure
Keith

You can never have too many tools in your life, except the two legged variety
I'm never wrong, once I thought I was but I was
mistaken.
Phil Churchett winner 2013


You can never have too many tools in your life, except the two legged variety
I'm never wrong, once I thought I was but I was
mistaken.
Phil Churchett winner 2013
Re: Brake light failure warning switch
According to the Kawasaki wiring diagram I’m using, the idiot light bulb doesn’t have a permanent earth, it has a permanent 12v which it shares with both brake light switches and the lamp is earthed via the green and white wire from the failure warning device.
The 12v to the brake light switches is switched to the rear brake light bulb via the blue wire and the bulb itself has a permanent earth. (0v)
With this in mind it does appear the the failure warning device is providing the normally switched earth permanently which is why I wanted to try and bench test the unit.
Cheers.
The 12v to the brake light switches is switched to the rear brake light bulb via the blue wire and the bulb itself has a permanent earth. (0v)
With this in mind it does appear the the failure warning device is providing the normally switched earth permanently which is why I wanted to try and bench test the unit.
Cheers.
- warren3200gt
- Hardcore
- Posts: 3049
- Joined: 13th Jun 2014
- Location: Dartford Kent
Re: Brake light failure warning switch
For it to provide a permanent earth through the failure unit it would show continuity across the terminals wouldn't it?
PUM 488 June 2026
76 Z900A4, 77 Z650B1, 77 KZ650B1, 77 Z1000A1, 82 Z1000J2, ZRX1100R.
76 Z900A4, 77 Z650B1, 77 KZ650B1, 77 Z1000A1, 82 Z1000J2, ZRX1100R.
Re: Brake light failure warning switch
Keith has identified the correct testing procedure in the Z1000 manual which is great.
I’ll get onto that in the morning and let you know.
I’ll get onto that in the morning and let you know.
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