brake lights wont work

[cass]

i have a 99 k3500 and cannot get my brake lights to work. i have replaced the brake light switch and still no luck. i can hear the relay clicking but does that mean its working? i also bought a new turn signal switch and it didnt fix it. the turn signals work. how do i check the relay? any suggestions? thanks cass

[Hubert]

Do you have an add on hitch? Have you checked grounds at the back of the truck. Look for blown fuses on side of dash and under the hood.

Did it blow the bulbs or are they good? Do reverse lights work? Do any of the lights work? 3rd Brake light work? Do you have a test light or multimeter?

[cass]

rear turn signals work, no fuses blown, 12v going to brake controller, installed new turn signal switch, new brake switch, and the relay clicks when the brakes are applied. i have swapped a relay of the same type and still no good. i understand the turn sig switch is when the power comes from to the rear lights but i havent isolated the wires that are supposed to send it out unless its the green and yellow. i have checked those on the switch and there is no power on those when brakes are applied. i may need to try to use an ohm meter to isolate the wire that sends power to the switch for the brakes. thanks for your reply cass

[Barry Nave]

Towards the rear pull the conectors apart and check for power there. May need a good cleaning.

[HowieE]

If your rear turn signals work that checks out all wiring from the signal switch back to the lights. That circuit is feed from a different fuse than the stop lights. Check fuse #1, 15 amps that is the stop signal fuse. If the fuse is good check the voltage output from the stop switch when the brakes are depressed. That is a white wire or look at the center brake light as it is feed directly from the stop switch and will prove the switch and fuse

[cass]

turns out it was the turn signal switch and the relay. i had been replacing one or the other but not both. both corrected it thanks to all who responded. cass

[Barry Nave]

:cool: