Wont start no lights 2006 suzuki c90 t

Begin with checking the fuse, then an inspection of the cable ends, then the relay. Perform a voltage check before and after the relay and chase the voltage down to where it stops/fails to go. If you make it all the way to the starter with good voltage then the starter is bad. You'll be checking bother the big wire, and the smaller one which energizes the starter. The smaller one interacts with safety switches at the kickstand, clutch and gearbox.
Take your time and work from the battery to the starter.

F1 is only saying check fault codes, you should have a small whith block connector some where under the seat, u need to use a bit of wire, place in the terminals like arc out, and then turn ignition on, on the dash it should show a fault code, if 00 no faults so look into fuel filters, blockages, water in fuel tank.

open headlight.. theres a plug in there that's for the spare circuit (take lens off front of headlight- 2 screws one either side

COuld be a bad battery or there is a loose (or corroded) connection somewhere. Check to be sure everything is tight, and clean on the battery terminals. If this happens after short trips, or after trips when your bike sat for a while, or on colder days it's probably just time for a new battery.

As long as the lightbar's power is less than 50 Watts and you secure it with it's own seperate fuse (5Amps for 50 Watts) I believe you don't have electrical issues. Use seperate lines directly from the battery and use a switch to turn it on only when your engine is running. Of course you may have warranty issues with your dealer if you install it.

The 1st thing i need to do is clarify what you mean by "won't trun over" do you mean the starter motor spins the engine and it will not fire up or that the starter doesn't trun the engine over? If the starter doesn't turn the engine over do you hear a clicking coming from the starter solenoid when this happens? If so replace the starter solenoid the heavy electrical contacts are burned.

Your starter button is a two position switch. The lights are supposed to go dim when the button is pushed halfway in. When pushed in all the way it should activate the starter solenoid. The starter solenoid is located under the seat next to the battery. You can follow the positive battery cable directly to the starter solenoid. If you push the starter button and the starter solenoid clicks, then the starter button is good. If the you unplug the two smaller wires going to the starter solenoid and connect a voltage meter to the main harness leads , the needle should jump whenever you press the starter button. If it does not clean the button contacts or replace the right switch assembly. If the starter button is good then take a jumper wire and short across the two battery cables on the starter solenoid. This will put power directly to the the starter. If the starter works now replace the starter solenoid. If your starter still does not work, try holding the starter button and tapping on the starter with a plastic hammer. If the starter works now then you probably need to replace the starter brushes. If anything else is wrong with the starter you will need to replace the assembly as the dealer will usually only offer the starter brushes for repair purpose.

check cut/safety switches . not sure about the circuit on this model but could be the side stand switch or the brake switch (on the handle bar)also check the rear tail light bulb is working when brakes applied. good luck...spaz.......Regards.....tabbycat