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jazzmaster, ASE Certified Technician
Category: Chevy
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1994 Chevy S-10 Pickup, Problem is there is no rear brake lights,

Resolved Question:

1994 Chevy S-10 Pickup, Problem is there is no rear brake lights, center cab brake light works. Turn signals work, hazards work, running lights work. I have tried new blinker switch under steering wheel. Wiring going to rear are dark green, light green, brown, yellow, and yellow(yes 2 yellows) one yellow is not connected at the harness plug. But does light the test light when brakes are applied. Yes and I have replaced the bulbs and check them.
Submitted: 7 years ago.
Category: Chevy
Expert:  jazzmaster replied 7 years ago.

hi I am including some wiring diagrams ,your yellow wire is for the left turn /brake and the dk green is for the right one,the other yellow wire is for an aux use, I would first check right at the rear brake light assemblies for 12 volts on the yellow (l) and on the right the dk green ,if you have the 12 volts there when the brakes are applied ,this comes right from the turn/hazzard switch,which you said you replaced,so also check at the harnes at the steering column for 12 volts coming out of the switch at the connector on both sides of the connector,if the voltage is there when the brakes are applied then look under the truck on the drivers side at the wiring for any obvious wiring defects ,bare wires or corroded wires, but getting back to the rear wiring ,check for 12 volts with the braks applied at those 2 wires right at the brake light assemblies ,if there is voltage there then check the assemblies themselves for broken or corroded wires, if,the white wire from the brake switch has 12 volts then that is working correctly..just follow these diagrams ...guy..



Customer: replied 7 years ago.
What i need to know is what color wire is power to the brake switch and what color is outlet power. I also need to know where the outlet power goes to next. If it is the turn signal switch or something else. I only have one wire with power at the turn signal switch with the brake pedal depressed. Key off.
Expert:  jazzmaster replied 7 years ago.
ok the wire is orange that goes into the brake switch and when the brake switch is pressed the white wire should have power to it (going out) ,if you have no power from the turn signal switch on the other yellow wire and the dark green wire,that other yellow wire is for an aux power off the brake light and also connects to the 3rd (center cab light ,I suspect that the turn signal switch is bad ,so chech for 12 volts with the brake pedal on at the yellow and dk green wires at the connector onthe steering column ...guy..
Customer: replied 7 years ago.
The only wire with power is the brown wire at the turn signal connector with brakes on or off.
Customer: replied 7 years ago.
Sorry, i do have power at orange and white at brake switch.
Expert:  jazzmaster replied 7 years ago.
the wiring I gave you is for a 94 s-10,what are the colors of the wires from the turn signal switch and what are the colors of the wires at the brake switch and does this have cruise
Customer: replied 7 years ago.

No cruise, wires at brake switch are orange white purple and pink/white strip. Turn signal switch are white, dark green, yellow, purple, brown, dark blue, light blue, black ,light green, light green/brown strip. Also I would like to know if I can raise the pay. You are really working hard for me and I really appricate it.

Expert:  jazzmaster replied 7 years ago.
there is always the option of leaving a bonus if you are satified with my answers .there should only be two wires at the brake switch ,
Customer: replied 7 years ago.
The 4 wires are in a factory plug. The 3rd brake light seems to be on a seperate relay under the dash. I dont know if that has anything to do with the problem. Again, i have power in and out of the brake switch. Per plinker switch- only brown to switch has power, nothing else.
Expert:  jazzmaster replied 7 years ago.
ok I was looking at the diagrams again and the wiring brake light switch you gave me is for a switch to the brake pedal for cruise control ,there should be another switch right near that one with just 2 wires ,you might have to look closer the 2 wires are orange (in) and white (out ) the relay is for the center cab brake light ,but when you first posted your question you said that the wires going to the rear were ,dk green,lt green,brown,yellow and another yellow,so we know that the other yellow is for an aux add on ,the brown is for lights(tail) the yellow is for the left brake/turnsignal,the right brake/turn signal is dk green,I dont see the lt green on the diagram but lets concentrate on the dk green and the yellow wires,I still suspect the turn signal switch ,you can try wiggling the turn lever while pushing on the brake pedal and see if the brake lights will come on ,even is only for a second ,also try working the hazzard switch for the looking for the same results,sometimes the switch gets dirty and will lose contact for the brakes but not the 3rd brake,it is possible that the column was switched and some point and thus the truck originally came with cruise,the colors you gave me were for a cruise control switch that is mounted near the brake pedal ,,SO with the brake switch pressed there should be power on the dk green ans yellow wire ,you could also see it it gets power to those wires when you wiggle the turn signal lever ,
Expert:  jazzmaster replied 7 years ago.
I have to go to bed work calls so check those wires and check if there is( power) at them then at the rear assemblies, then you have to if there is power in frt but not in the back look under the truck and look for corroded or broken wires,but I still think it is in the turn signal switch ,so we can continue this tomorrow .....guy..
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