brake light problems

[liran]

Hi guys,
i'm so frustrated from this issue...
so i noticed a few days ago that only the tail light is working and when i hit the brake (both of them) nothing happens...
after googling it for a week and trying all of that:
1. change the bulb
2. change the bulb to LED bulb
3. electrical connector spray

i understood that it's not the reason for why it's not working.
i also took the front brake lever switch off, and tried to directly connect the two pins, then the brake light came on. so i tried a random switch that i had and it worked at well when turning the switch on but the rear brake won't initiate the brake light so i also detached the connector below the sit, directly connected the two pins and it also worked.

at that point i can't understand what's the source of the problem. i do have a multi-meter at home, but i'm not sure where i should check and what's the result i should get.

help. please. i'm desperate.

[TPEHAK]

Check Brake-horn fuse.

Also check key switch relay.

If it is OK just open service manual, find main harness wiring diagram and follow the wires from brake light and brake levers switches to understand how it works. Then use your multimeter to check continuity between wires where it should be. Once you will find the area without continuity, start narrowing it until you will find the issue. You can also take a shortcut and check if there is a 12V current between ground and Brake-horn fuse when switch key is ON to make sure the wires and relay before the fuse are OK.

[TPEHAK]

-check if there is 12V between Brake-horn fuse and ground when key is ON (just hit your horn button, no need to use multimeter, your horn will check relay and fuse simultaneously)
-if it is OK turn OFF the key and check continuity between ground of the motorcycle (or ground of battery) and black wire on the brake light or brake light plug
-if it is OK the issue is here, check the brake light wires continuity

This picture is for 2009 Buell XB 12 Scg. You need to find service manual for your motorcycle. The wires color might be different, but the circuit configuration is probably the same

It is very easy shouldn't take more than 5 min to find the issue

Also check the light bulb socket itself, probably even before checking the wires, the issue might be right there.

Also check the bulb itself, maybe before the wires too.

[user_deleted]

Hi guys,
i'm so frustrated from this issue...
so i noticed a few days ago that only the tail light is working and when i hit the brake (both of them) nothing happens...
after googling it for a week and trying all of that:
1. change the bulb
2. change the bulb to LED bulb
3. electrical connector spray

i understood that it's not the reason for why it's not working.
i also took the front brake lever switch off, and tried to directly connect the two pins, then the brake light came on. so i tried a random switch that i had and it worked at well when turning the switch on but the rear brake won't initiate the brake light so i also detached the connector below the sit, directly connected the two pins and it also worked.

at that point i can't understand what's the source of the problem. i do have a multi-meter at home, but i'm not sure where i should check and what's the result i should get.

help. please. i'm desperate.

liran: contrary to all the jibberish above the key switch relay and other assorted mumbo-jumbo has no bearing whatsoever on your very simple problem. all of your brake components including the F&R switches are nissin items. your front brake switch is a simple button circuit switch....your rear switch is a pressure modulated switch.
if i'm understanding you correctly you removed the front switch and replaced with a generic spare and you then had functional brake light? if that's correct simply replace the OEM switch. readily available....crosses over to many jap bike applications...only a few $. be sure it is mounted correctly and that the lever tang just barely touches the switch button when installed.
again if i'm understanding you correctly you went thru same procedure with rear pressure switch and got a functional brake light? correct? the pressure switch is either clogged or faulty. remove it and replace. again readily available and reasonably priced. you can try spraying cleaner into the fluid port, blowing out with compressed air, and reinstalling to see what you have but it's a hassle and i prefer to just replace it.
lastly....closely check your harness to rear tail light plug under the seat area. it's susceptible to dirt and corrosion and if compromised you'll have no brake light. IF YOU NEED the part numbers for front and rear switches i have them.