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Discussion Starter · #1 ·
Well guys,
my ST4s 2003 start but with the switch off the lights and idiot lights are still on.I switched the ecu nothing,i removed the30 main fuse and everything is going off but if i turn the key to on and off the lights remain.I am lost.Any ideas? Thanks.
 

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Its possible the ignition switch is bad. I would start there with a voltmeter. With the ignition off (everything off) identify which wire is a constant 12 Volts. Turn the ignition on and identify which wires then turn on 12 volts. Turn the ignition off and notate what happens with the ignition wires.

If the ignition wires remain with 12 volts after the ignition is turned off, I would then disconnect the harness at the ignition and see if everything shuts off. If so, it's most likely the ignition switch. You should be able to measure continuity on the switch to confirm this.

If you see power removed from the ignition wires once you shut off the key switch then move down the line, possibly a stuck relay.

I am not familiar with you bike but those are the basics I would start with. If you dont have a meter or know how to use one, I would replicate the issue and turn off the key switch then unplug and see if it turns off the lights. Start there.
 

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I agree with the key switch. One easy thing you could do is to try is flushing it out with electrical contact cleaner. You can get some stuff at NAPA in a spray can by CRC that leaves no residue. Disconnect the neg battery post and hose it out through the key hole. Use the key to cycle it on and off a few times, repeat. The stuff drys pretty quick, but maybe wait a bit then connect the battery and see what you get. Good to displace any water and clean any corrosion that may be in there. Place some rags under the switch too, just to keep it from running on to something you'd rather not have it run on to! Doesn't seem to harm paint or rubber, however.

You can also unplug the key switch and remove it if needed. Plug is white multi pin under the right faring on my bike.
 

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Had the same problem - in my case, it was a relay, one of the ones up front to the left of the headlamp. It had simply popped. I replaced it, and life was good.

Ron
 

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Had the same problem - in my case, it was a relay, one of the ones up front to the left of the headlamp. It had simply popped. I replaced it, and life was good.

Ron
This is what I was thinking is very likely, say it arched itself together. I have seen the ignition switches go bad so I'd assume to start at those two places and hopefully its a cheap and easy fix.
@burnjonas please keep us updated.
 

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Yeah the headlights go through the main relay which on my ST4 is to the left of the instruments and is yellow.
 

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Discussion Starter · #7 ·
Some news,i switched relays and the lights are still on,waiting for a ignition switch for more tests,should know by thursday.
 

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Some news,i switched relays and the lights are still on,waiting for a ignition switch for more tests,should know by thursday.
Sounds like the ignition switch. That means the switch most likely is still sending power after the key is removed. I've seen this before on vehicles but not a bike. Hopefully that is the issue.
 
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