Brake Lights not working

[Rox Crusher]

I recently made the mistake of disturbing the rats nest of wiring under the dash while replacing intermittent wiper switch. The relay / control box for this switch, along with a big relay for power antenna, have always hung dangerously low near the skinny pedal. So I got out the trusty zip ties to tie them up higher, and apparently pulled one of the wires out of the connector for the brake switch while doing this.

I have running lights, turn signals, but no brake lights. Also, emergency flashers work up front but not out back. I discovered the brake light issue while on the road to Bronco Safari (awesome event).All lights were working properly before I fooled with the wiper switch.

I clipped off the wires to remove the OEM connector, replaced with female spade connectors, and installed them onto the switch. I get power to one side but pressing pedal doesn’t result in brake lights. I then temporarily used a wire to test / bypass the brake switch and still no brake lights.

so now I’m guessing the problem is downstream of the switch but I don’t know where to look next And I’m not wanting to unnecessarily disturb the rats nest and cause further damage. I’m hoping someone can tell me where to look next.

Also, anyone wants to offer opinion on best wiring harness currently available, that would be appreciated as well.

 

[DirtDonk]

So have you checked for power coming in to the brake light switch on one wire?
Did you check the Action of the switch? Either with a voltmeter or an ohm meter?
Jumping them together should’ve resulted in something, but only if there’s power on one of them to begin with.
That power comes from the headlight switch, which can sometimes fail in it’s connection.
If you verify there’s power and still have no brake lights when you jumper the two connectors, leave them jumpered for the time being.
With the key off, but flipping the turn signal switch to one direction or the other (or still better, try both) and see if the brake light turns on in that direction.

But double check the switch first. Unless I missed it when I read your post and you already did?

 

[Rox Crusher]

So have you checked for power coming in to the brake light switch on one wire?
Did you check the Action of the switch? Either with a voltmeter or an ohm meter?
Jumping them together should’ve resulted in something, but only if there’s power on one of them to begin with.
That power comes from the headlight switch, which can sometimes fail in it’s connection.
If you verify there’s power and still have no brake lights when you jumper the two connectors, leave them jumpered for the time being.
With the key off, but flipping the turn signal switch to one direction or the other (or still better, try both) and see if the brake light turns on in that direction.

But double check the switch first. Unless I missed it when I read your post and you already did?

Howdy Paul, yes we had power on one of the wires to the switch. I didn’t test the functionality of the switch itself. Instead, we bypassed the switch altogether with a short piece of wire to test if we got lights without the switch in the mix.

I‘ll give your test a try

 

[EPB72]

as Paul said,, and to add check at the TS conector at the base of the steering column, if you indeed have power to brake switch and power out or jumped ,id use a test light back probe both sides harness side and Turn signal switch side ,,, {{ this is a common place for poor connections/corroded terminals ...

 

[Brush Hog]

Reverse the wires on the brake switch. They might have got swapped when you re did the connectors. Also if you took brake light switch off and put it back on upside down your brake lights might stay on all the time or not activate when you push the pedal. I’ve had all 3 problems before.

 

[Broncobowsher]

The brake light switch output goes to the turn signal switch. That way when you use the turn signal switch, it dsconnects the brake light from that side and connects that side to the front turn signal and blinking power.

The loss of rear hazards also points to the turn switch. Turning on the hazards puts blinking power off the hazard flasher (different than the turn flasher) to 3 places. Left front, right front, and brake lights. The fact you are not getting hazards out the back points to the brake signal issue getting into the turn switch if not the turn switch itself. Operating properly, applying the brake while the hazard is on will over ride the hazard and be on solid. Being the brake is tied to the fronts with hazard on, the brake will back feed the fronts and they should stay on solid as long as the brake is applied.

My guess is you broke a connection between the brake pedal and the collum connector when you wiggled the wires. Bet the turn switch was replaced sometime in the past and the connector was replaced with a handful of butt connectors, which isn't a bad connector if installed correctly. But few install them correctly and the wire falls out.

 

[Rox Crusher]

The brake light switch output goes to the turn signal switch. That way when you use the turn signal switch, it dsconnects the brake light from that side and connects that side to the front turn signal and blinking power.

The loss of rear hazards also points to the turn switch. Turning on the hazards puts blinking power off the hazard flasher (different than the turn flasher) to 3 places. Left front, right front, and brake lights. The fact you are not getting hazards out the back points to the brake signal issue getting into the turn switch if not the turn switch itself. Operating properly, applying the brake while the hazard is on will over ride the hazard and be on solid. Being the brake is tied to the fronts with hazard on, the brake will back feed the fronts and they should stay on solid as long as the brake is applied.

My guess is you broke a connection between the brake pedal and the collum connector when you wiggled the wires. Bet the turn switch was replaced sometime in the past and the connector was replaced with a handful of butt connectors, which isn't a bad connector if installed correctly. But few install them correctly and the wire falls out.

Turn switch was indeed replaced years ago. I’ll look into this. Thank you for your detailed insight.

 

[Rox Crusher]

The brake light switch output goes to the turn signal switch. That way when you use the turn signal switch, it dsconnects the brake light from that side and connects that side to the front turn signal and blinking power.

The loss of rear hazards also points to the turn switch. Turning on the hazards puts blinking power off the hazard flasher (different than the turn flasher) to 3 places. Left front, right front, and brake lights. The fact you are not getting hazards out the back points to the brake signal issue getting into the turn switch if not the turn switch itself. Operating properly, applying the brake while the hazard is on will over ride the hazard and be on solid. Being the brake is tied to the fronts with hazard on, the brake will back feed the fronts and they should stay on solid as long as the brake is applied.

My guess is you broke a connection between the brake pedal and the collum connector when you wiggled the wires. Bet the turn switch was replaced sometime in the past and the connector was replaced with a handful of butt connectors, which isn't a bad connector if installed correctly. But few install them correctly and the wire falls out.

Howdy Broncobowsher (and everyone else)

i tried a few things today without resolution.
- confirmed continuity of the red black wire from brake switch to horseshoe connector, all good
- confirmed continuity of red black wire on other side of horseshoe connector, all good
- jumpered power from red wire from light switch that feeds power to brake switch, to red black wire at back side of connector that feeds to turn signal switch Still no brake lights.
- removed steering wheel. Found horn wire disconnected / broken loose from horn contactor ring. looking at schematics I don’t think this has anything to do with the brake light problem but I’m not sure

any other insights for me to consider / things I should check before replacing turn signal switch?

 

[serial car restorer]

Jump 12v hot to the yellow/black and solid green wires coming out of the turn signal switch. If the brake lights work (yellow/black is left, green is right) when jumped, the switch is bad.

 

[Rox Crusher]

Jump 12v hot to the yellow/black and solid green wires coming out of the turn signal switch. If the brake lights work (yellow/black is left, green is right) when jumped, the switch is bad.

I got both brake lights when I jumped the 12v to each of these wires separately. Thanks for your help! New Old Stock turn signal on the way!

 

[Rox Crusher]

Well, mystery solved. I took the column apart and found that the collar for my aftermarket steering wheel had come a little loose. It allowed the green wire to get pinched under it and broke the wire.

ok, separate but ”since I’m in there”……..the upper bearing is a little loose / sloppy. Can it be removed and replaced without taking the column out etc?

 

[serial car restorer]

That explains the lack of right side brake light, but not the left. Green wire has nothing to do with the left side.

 

[DirtDonk]

Not sure on the bearing, but it might also depend on what year.
What year is your bronco again? They utilized a couple of different bearings over the years, and a couple of different attachment methods.

 

[Rox Crusher]

That explains the lack of right side brake light, but not the left. Green wire has nothing to do with the left side.

I went back and inspected the yellow / black one closely and don't see any obvious problems with it. Later, when I have time I will check it for continuity. Also, I wanted to get your thoughts on the results I got when I jumpered the hot wire to these two wires (individually).

When I jumpered the each wire individually, both brake lights came on. Based your answers so far, this shouldn't be the case. Is this correct?

Sorry for pestering you with all the questions but I really enjoy learning and your expertise is very appreciated.

 

[Rox Crusher]

Not sure on the bearing, but it might also depend on what year.
What year is your bronco again? They utilized a couple of different bearings over the years, and a couple of different attachment methods.

1977. It has a snap ring and a washer holding it in.

 

[serial car restorer]

When I jumpered the each wire individually, both brake lights came on. Based your answers so far, this shouldn't be the case. Is this correct?

If the green wire was cut completely through during that test, then no, they should not both have come on. I suspect you have a bad ground to the rear lights as well.

 

[Rox Crusher]

If the green wire was cut completely through during that test, then no, they should not both have come on. I suspect you have a bad ground to the rear lights as well.

Weird thing is, the green wire still had continuity.

but new turn signal switch solved it

thanks again for all your help

 

[DirtDonk]

Weird thing is, the green wire still had continuity.

Common thing to happen.
There could’ve literally been just one strand of the wire, still touching the other, and your meter would’ve sensed continuity.
Not enough to pass electricity to work, the lights, but the meter doesn’t put any real load on the circuit.