Brake lights not working

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jcsquare

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Need help please. My brake lights does not come on. They use to work. No wiring changes made

Tail lights, park lights, turn signals, flashers, instrument lights work.
Put in a new fuse, replaced brake light switch(has continuity) both wires are connected .
Right and left bulbs are fine.

Where do I go from here?

Thanks in advance for any help.
 
Might be in the turn signal switch. I think the electrical section has more about how this works. MT
 
If the tail lights work your ground is OK. Do both rear turn signals work? If so the bulbs, wires and fuses are OK. That would leave the switch on the brake pedal or the turn signal switch and it's connector coming out of the steering shaft.
 
I tend to think its the brake light switch. You should only have continuity (or 12V) on one side of the switch when the brake pedal is at it's normal non depressed position. I'd suggest readjusting the switch, rotating the switch plunger against it's mating contact as they can lose continuity from shelf time, and or reverse the two wires since you may have them crossed. Generally if the turn signals work the turn signal switch is likely good. Of course no guarantees.
 
jcsquare said:
Need help please. My brake lights does not come on. They use to work. No wiring changes made

Tail lights, park lights, turn signals, flashers, instrument lights work.
Put in a new fuse, replaced brake light switch(has continuity) both wires are connected .
Right and left bulbs are fine.

Where do I go from here?

Thanks in advance for any help.
Click to expand...

Voltmeter. One side of switch should have 12V at all times. Press the pedal. voltage should stay on. If not you have a power supply problem, IE fuse bad connection etc

Move meter to "cold" side of switch. 12V should appear as pedal is pressed. If nothing, bad switch or out of adjustment

If you have that voltage, make certain it is getting through the connector to the TS switch. Cycle the hazard switch on/ off a few times. Make sure hazards are off and switch is centered.

If all this shows good, and signals work, it is a bad TS switch
 
Thanks guys?...I will check all of the above to pinpoint the problem. I will report my finding in a few days ��
 
I just went thru this on a 66. If there is power going thru stoplight switch, OP stated there is, AND both turn signals work, STRONG possibility the turn signal switch is bad. That switch is a hell of a design. I have opened it up and all I can figure is someone was drinking when they thought that up. BUT it does work. MT
 
What amp fuse should I be using. My car shows 3amp fuse in the brake slot. I have another harness for the same model car with a 6 cyl that shows a 20amp fuse. Which is correct.

Bottom line , no power to the brake light switch yet everything else associated with the TS works
 
Not 3, lol 15 at least and probably 20. Your service manual tells you what all is on that fuse
 
I agree that 3amp is too small. Just cannot figure out why it is clearly stamped 3 on the fuse box.
 
Most people do not realize that current flows through the brake light switch and then into the turn signal switch. Your problem could be the turn signal switch OR the turn signal cancelling cam. The turn signal cancelling cam has two wires going to it. One wire is hot when current flows through the brake light switch and the other is hot when the ignition switch is 'ON'. The 'Brake Light' power flows through the cancelling cam wire and then goes through two hard wires about 1/2 inch long on the back side of the cancelling cam that (when properly aligned) each touch two little bumps (or contacts) on the top of the turn light switch. There are actually 4 little contact bumps on the top of the turn signal switch - two for the front turn signals (left two I think); and two for the brake lights (right 2 I think). Brake light Power then flows through the bumps (contacts) the rear brake lights. You will clearly see what I mean if you take off your steering wheel and look at the bottom (back) side of the turn signal cancelling cam and the top or the turn signal. Or you could look the parts up individually on Ebay and see them. FIRST, make sure you have 12 volts flowing through the brake light switch when the pedal is depressed. Then pull your steering wheel and leave the cancelling cam in place. With a current tester, check to see if you have power flowing through one the wires on the top of the cancelling cam (the one on the right I think). If you do have current, you are halfway there. Now pull the cancelling cam and turn it over. For the wires to touch the contacts, they must be sticking out a bit. Test the rest of the circuit by jumping current from the canceling cam back wire (with brake pedal depressed) to the contact bumps the hard wires would have been touching one at a time. If the brake lights work, then your turn signal switch is likely working since it fed current to the cancelling cam and to the brake lights. In this case the cancelling cam may be the culprit since it appears to be unable to complete the circuit. If you have no current going to the cancelling cam or if jumping current to the contact bumps on the top of the turn signal switch did not allow current to flow to the brake lights, then you likely have a bad turn signal stitch.
 
I know my last post was long, but the wiring and diagnosis is fairly simple. I went through this with my 69 Barracuda. PM me if you want more specifics.
Mike
 
I was going to say I think power goes thru brakelight switch FIRST then turn signal switch. BUT it has been said! lol
 
harrisonm said:
Your problem could be the turn signal switch OR the turn signal cancelling cam. The turn signal cancelling cam has two wires going to it. One wire is hot when current flows through the brake light switch and the other is hot when the ignition switch is 'ON'. T
Click to expand...

Where exactly are you getting all this from?
 

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Check the Emergency flasher (4-way) and see if it works. Ran into this on an old dodge diplomat where that flasher was bad and subsequently no brake lights.
 
jcsquare said:
Bottom line , no power to the brake light switch yet everything else associated with the TS works
Click to expand...

The power wire that feeds the Hazard flasher also feeds the brake light switch, according to the wiring schematic that should be a pink wire.
If the Hazard flasher works , there has to be a problem with the pink feed wire going from the Hazard flasher to the brake switch.
 
Finally got it working. Since no power was going to the brake light switch, I ran another pink wire from the same location on the fuse box to the brake light switch. Evidently the original pink wire has a break in it.

I hope what I did does not cause any future problems.


Thanks everyone for you help
 
I'd definitely vote: Turn Signal Switch (TSS).
a) It may have been fried (I know I'm guilty of it)

b) It may also be due to a previous owner doing some re-wiring. So check that the TSS wires match.

c) To Compound matters, Some aftermarket TSS wire colors don't match. But fear not, here is a link from Sweptline.org (scroll down to the 'Eighth Topic')
c1) Note that the Author of that thread also found a source for TSS at a reasonable price (anytime Sweptline guys give a parts source, you know the price is good...'cause we're really cheap, even more than A-Body guys - I'm actually both). Oh, the company name is 'Shee-Mar,inc.'

d) The problem could be any combo of the three + more, esp. the Bulkhead Connections (get rid of as many as you can - at least the Ignition & Lights)

Good Luck - This part of owning a Mopar is the absolute worst part of these cars. I'll take Rust issues over Elec, anyday.
 
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