ive been trying to research my left brake light not working for a while now. ive replaced the bulbs and the brake light switch. the left turn signal works, but not the brake light. someone said the multifunction switch (turn signal switch) sends power to the brake lights when used and it is a common failure. has anyone had any experience with this issue and solution or any other suggestions? just trying to pick brains before i spend $150 on something that wont fix my problem.

 

I don't know how rusty your Blazer may be,but make sure the bulbs are inserted the right way! I went through this about a year ago,my bro just had the same prob on his Jeep! Bulbs inserted the wrong way! Other than that:wiring! Good Luck!

 

I just found out today I have that exact same problem, have u found a solution?

 

i havnt resolved the issue yet, my brake light seems to work when it wants to. word has it that the power for the brake lights feeds through the turn signal switch, im guessing its so that when you have your brakes on and turn your blinker on it reroutes power through the turn signal relay. either way my blinker acts really weird if i dont click it into place, if i just hold it up so my right blinker comes on it blinks really fast on only 1 bulb, but if i click it all the way into place its fine. i'd imagine my switch is going out.

it could also be a bad brake light switch, i replaced mine and nothing changed, but may not be the case for you.

 

I'm thinking is the multi function switch too because a couple of weeks ago I started having problems, most of the time I put the turn signal to the left it would not work unless I apply some downward pressure on the lever, I just ordered a new one since anyway I was going to replace it.

 

Check for voltage AND ground at the bulb socket, gotta have both for it to work The ground terminal in the socket must have less than 5 ohms resistance to body ground.

The stop lamp switch supplies voltage for both sides simultaneously, so if one side works, the switch is fine. Voltage from the stop lamp switch is split in the multifunction switch and sent to the stop lamps on separate circuits. If the socket ground is ok, test for voltage coming out of the multifunction switch going to both stop lamps.

 

My problem is solved, it was the multifunction switch

 

Not necessarily, I had two brakelight switches go bad where the left brake light was the only thing not working, did not make much sense but that is the truth

Try another brakelight switch and make sure your wire pigtail to it is corrosion free

 

And my old SVO ran a lot stronger every time I washed and waxed her.
You mean you had two flaky turn signal switches where if you changed the brakelight switch it worked for a while. And I believe that. But if your battery was low it would be same thing. For that matter it might have been a flaky lamp socket.
One wire in, one wire out.

 

I admit it didn't make any sense to me either why only one side worked, maybe I had a bad connection somewhere. To be completely honest, the brake light would work if I gently pushed towards dash on the turn signal stalk. I did not change out stalk, just brakelight switch, and it started working, the brakelight switch is wired through the multifunction switch and has 6 terminals on it, but only two wires?

It is all crazy