What's up fellas, got brakelight issue, that has become a real drag. I have a 66' Malibu I partially restored, partial meaning still saving money for the Tuxedo Black paint job I want and we all know how expensive the body work get's to have that paint job look right. Anyway I bought all new wiring for the engine, front and rear lighting. But sadly the dash harness is 40 years old, it looked fine when I had interior stripped out, and the price tag on a new one wasn't really in the cards at the time. But my problem is that my left brake light fails to light when standing on the brakes. The blinker on that side works along with every other rear light. Which kinda leads me to believe that it's somewhere in the dash. Orange wire at stop switch has contant 12, white wire has nothing when pedal depressed, Had a short in the past, when the tag light wire rubbed into the rear body pinch weld, fried the bulb in the left rear something awful before the fuse blew. Put new fuse in it and all lights worked fine for a short time, and now the left rear brake is the only light not working. All the grounds are fine, so I got a feeling I'm gonna have to spend a few hours digging out the dash harness and untaping and poking wires, so any advice you guy's can give me would make me feel somewhat better about this fiasco.

sounds like your problem could be with the turnsignal switch, check the brake light input/output voltage@ the steering column harness connector.

............my left brake light fails to light when standing on the brakes. The blinker on that side works along with every other rear light. Which kinda leads me to believe that it's somewhere in the dash. Orange wire at stop switch has contant 12, white wire has nothing when pedal depressed,

which means the stop light switch is not working.

Had a short in the past, when the tag light wire rubbed into the rear body pinch weld, fried the bulb in the left rear something awful before the fuse blew.

A short in tag light could not effect the bulb in the left rear (except to blow the taillight fuse).


Put new fuse in it and all lights worked fine for a short time, and now the left rear brake is the only light not working.

I don't see how the Right side brake light is getting power when there is no power coming out of the brake light switch
:confused:

All the grounds are fine, so I got a feeling I'm gonna have to spend a few hours digging out the dash harness and untaping and poking wires, so any advice you guy's can give me would make me feel somewhat bette

I would get the stop light switch working first I think.

Ok, apperently my volt meter took a big dump, got another and have 12 volts at stop switch white wire when pedal depressed. The odd thing is that the brake light will work if I hit the blinker and tap the brakes a few times on that side. Gotta be a ground or a broken wire right or what?

I don't know if the Left turn wire is yellow or not on a 66, might be black/yellow but IF that wire is dead coming out of the turn signal switch, then it's probably as Vince said, a bad switch or possibly a poor connection at the column connector.

The problem for me usually is if it works part of the time it will work everytime when I try to check it.

Make sure the housing and sockets are absolutely clean. A little corrosion causes odd operation.

Okay checked voltage at column harness 12 volts constant at black wire, white and dark green have 12 when pedal depressed, checked votage at ribbon connector, brown has twelve with lights on, dark green twelve with pedal depressed, orange has contant twelve which is the dome light. One of the other weird things is when I test the cream colored wire at the ribbon connector, which I believe is the fuel sending unit, it jumps the fuel gauge up to the full mark, until I move the wiring at the ribbon connector, it then resets itself. Trying to find my wiring diagram, don't have a lot of time to work on it during the day. When i put a test light instead of volt meter to black wire out of column harness it slightly puts voltage to the horn I here it for a split second. And when I get the left brake light working by tapping the brakes with the blinker on, I here slight radio interference the second i step on the brake. When I get the brake light to work it almost seems like it's getting too much juice. It's a lot brighter than it used to be. Haven't checked the voltage at the socket yet, will first chance I get. I swear I'd rather eat dirt than deal with elctrical problems.

I had the SAME problem recently. The turn signals worked/blinked right and left. When I tapped the brake, only
the right side came on. I checked the wires all the way back to the switch in the column. I took the steering wheel
off and checked the switch.

The contacts in the switch mechanism (thin metal strips) were dirty/corroded. I chose to clean
the contact points in the switch, problem solved! The curcuit goes from the fuse box, through the
brake switch, then through the turn signal switch, then out to the rear bulbs.

I'm bettin' your switch is the culprit.

I just re-read your last post. The turn signal and brake light share the same circuit from the Turn Signal Switch back
to the Bulb. If your Left turn signal flashes the bulb, that circuit is good for the brake light as well. (your back to that switch again!).

If you used a test light to check the wire for the fuel gauge, the test light grounds the circuit which would cause the
gauge to peg full.

Oh and the voltages for the blinkers as follows, Left side-brown,blue and yellow have twelve blinking, Right side-light green, dark green and brown have twelve blinking, black being constant twelve. At ribbon connector, Left side-twelve at yellow blinking, Right side-twelve at dark green blinking.

Thanks for the input Jim, right now I'm willing to do anything to get this resolved, inspection sticker is in the hole and getting real tired of staring into the rear view for those pathetic crown vics, had to put a stop to all the stoplight racing, beating mustangs never gets old.

Re-read my last post.

We were typing at the same time and I edited my post with more info.

Hope it's helpful.:)

Okay, took out turn signal switch, cleaned little brass contacts with fine steel wool, put it back together, and still same problem. Shouldn't the yellow wire be hot at the ribbon connector if the brake is depressed, being that the brake and turn are on the same circuit. It's yellow at the left rear socket. Dark green at the right. Does the white wire turn to yellow somwhere under the tape? Cause the dark green wire at the turn signal connector is hot when the brake is depressed and so is the white. I put a jumper from the white at the turn signal to the yellow at the ribbon connector and both brake lights work, but the left turn does not when engaged with the brake depressed, the right works fine with brake depressed. I guess I'm gonna have to find another switch and go from there, cause I'm really pulling my hair out here, and still trying to find my wiring diagram!:clonk: :angry: :confused: :mad: :sad:

Sounds like maybe the white is ground wire but somehow got shorted to turn stop wire. GM has used yellow as left turn and stop, and green as right turn and stop for decades and still uses these colors today. Try to jump yellow to batt and see if hot at rear. Do the same with green and check at rear. Do this with bulbs removed. It is common for wire tape to rear to corrode bad. This is more prevalent in areas that use road salt.

check out this link, you have to copy to your address bar, it won't hotlink; http://elcaminocentral.com/articles/wiring/691.gif
If you click on the picture it will enlarge.

You are correct that the yellow wire should have power when the
brake is depressed. The white is hot from
the brake switch to the t/s switch where it connects to the yellow
to go to the rear left bulb for turn/brake
light. If white is hot going in and yellow is NOT when the brake is depressed, the disconnect is in the switch.

Use a test light/'DVOM to check for power inside the switch on the actual contacts. That's how I found mine was
the problem. I had power on the metal strips from brake curcuit, but when I touched the other metal strip it was supposed
to be touching to put power to the yellow wire, there was no voltage.

I'll join in you're frustration.....:angry::angry: :angry:

Well gentlemen, the brakelight dilemma was solved actually last week, had to haul ass to get her inspected as soon as I figured it out. After racking my brain, I took everything apart again, and traced the yellow wire to it's post in the switch again. Looked at the brass contact through a magnifying glass and noticed it was tweaked ever so slightly, from the normal eye it looked fine, but upon further review it was off a you know what hair. Got it back into normal posistion and boom, problem solved. Thanks for all the input fellas, was shopping around for prices on new switch, but luckily I have the cheaper "GUIDE" other than the "BPC" switch. Gonna stick with original until it breaks for good.:beers:

SWEEEET!!!!!:hurray: :hurray: :hurray: :beers: