No brake lights

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Futzy1

Futzy1

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Hey guys FNG here. just bought my first mopar, and making my first post.

Anyway, I just picked up a green 73 4door dart, and the brake lights don't work. signals work fine, reverse lights mostly work, but no break light. I've read this could be a signal switch issue? any info is welcome, and thanks.
 
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I had a broken wire going to my signal switch in the column. You could check the wire going up the column to see if it is powered when the pedal is pushed. If there is power there, check for power on the wire coming back out the column for the brake lights.
 
Futzy1 said:
Hey guys FNG here. just bought my first mopar, and making my first post.

Anyway, I just picked up a green 73 4door dart, and the brake lights don't work. signals work fine, reverse lights mostly work, but no break light. I've read this could be a signal switch issue? any info is welcome, and thanks.
Click to expand...
Try checking continuity on the brake light switch which is located up above the brake pedal. Some switches are also adjustable with a double nut to set switch depth activation. Like the one in this pic.

brake switch.jpg
 
There's a white wire from that brake light switch going to the signal switch. Ignition switch off, With a test light, first prove there is power from fuse to the other wire of brake light switch ( I forget color ), then close switch and prove power on the white wire going into signal switch.
That same power should appear on 2 wires ( a green and a yellow ) coming out of the signal switch if/when that switch is centered. If the power doesn't pass through the signal switch from white to both a green and a yellow, that switch is the problem.
On rare occasion ( a work truck can't rest ), I have shoved a shirt pin through these 3 wire casings to generate working brake lamps temporarily so the vehicle could be safely driven while waiting for a new switch.
 
Well I'm an idiot. I have good news, bad news, and WTF news. The good news, I'm %90 sure it's a short. Fuse 4 is blown and every time I replace it it blows again immediately. The bad news is (assuming I'm reading it the service manual right) there is a ton of stuff in that circuit. Dome lamp, trunk lamp, map, lamp stop lamps, ignition lamp relay, ignition lamp, hazard flashers, etc. The WTF news all turn signals are working, and at least the front turn signals are on that same fuse, so why are they working???
 
I don't know the fuse numbers. I know brake lights are on a "hot at all times" fuse.
In most cases there is little to nothing more on that circuit. Maybe that changed in later models but in my opinion, There shouldn't be a lot of stuff added to the brake lamp circuit.
Turn signals are on a "hot at switch on" fuse.
And you short circuit could still be in the column. Manually operated switches are always suspect.
 
OK. well... I have to agree that some builds do have a lot of unnecessary BS added on. Sharing the brake lamp fuse just makes matters worse. Newer vehicles have separate circuits with umpteen fuses making them easier to diagnose.
Its easy enough to go under the column and disconnect the signal/hazard switch assembly. For a new fuse to stand or blow is a clue. A shorted lighter well would still blow the fuse.
You could spend a bunch of fuses that way. In further diagnosis, I would first remove the dome lamp bulb, then attach a test lamp across that fuse slot. When the short circuit disappears the test lamp goes out.
Good hunting.
 
Fish, thanks man. got it all fixed. well. . . .some of it. Good Ole case of fixed one, found another. The short was pretty easy to find once I knew where to look, you'll see it in the picture. It was on the glove box lamp part of the circuit. I'm just going to leave it disconnected for now. But in the meantime, fixing the short got my hazards back and my dome light. but the brake lamps still weren't working. Then I double checked the the switch and it was wired wrong. but woo-hoo brake lights.

20161113_223041.jpg
 
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