No Brake Lights
Everything works besides the brake lights and 4ways. I have replaced the brake switch, bulbs, checked the connection, and fuses and still no go on them.
Could the 4way switch be messing with the brake lights?
If the 4 ways are out, what about the turn signals?
Confirm there's power to the brake lights. This can be easily done with a 12v test light. Do what you need to do to access the lamp sockets. Have someone push the brake pedal or rig it so it's depressed, then see if there's power to the sockets with the test light. If there is, the test light will turn on. If there isn't, it won't. MAKE SURE you check both sockets, too.
Also, perform this test with the headlight switch on AND off, because that will help determine what the problem is.
If there IS power to the sockets... then it's probably a grounding problem. Check and clean grounding points- I'm pretty sure they're under the truck by the rear bumper. You may have to replace grounding wires and terminal connections, depending on their condition.
If there is NO power to the sockets... then it's a supply issue. You'll need to trace the circuit from the lamp sockets to the fuse box, which is where the power supply should originate. Contact Subford and give him the year and make of your truck- he's got all kinds of wiring diagrams.
Good luck and keep us updated. The more you tell us of your progress the better we can guide you to solve this problem.
Could it possibly be the turn signal switch? I read that the brake lights and the turn turn signal switch are directly linked







