No brake lignts and flasher lights at rear of truck

[behemoth]

We are trying to get the kids truck back on the road. We have all the lights, sidemarker, blinker, tail, backup, except brake in the rear and the rear flasher.

I have jumpered the switch on the brake pedal so they would be constant on and they are not so it is not the switch. We also took the switch from mine and it did not help.

What we have done is swap in a 75-77 auto column which is what I did to mine and it is wired the same.

The blinkers and brakes are on the same line are they not.

So I am somewhat at a loss as to what and where to look for it. I am starting to think it may be in the column wiring or blinker switch at the top of the column.

Any ideas as to where to look next ?

 

[Madgyver]

Did you check yor bulbs, Those can good bad as soon as you install them. One goes out and it interuupts the circuit.

Try and jump the lines with a hot line. Tap off something live in the rear harness and jump it into the brake light circuit. If that works than the problem is not in the lights but maybe in the wiring before that, maybe the flasher or wiring.

 

[behemoth]

I used all new bulbs, I will check them again. The odd thing about this is the blinkers work and the tail lights work. So both filaments are working. I have checked the wires all the way up to the dash. most of them to the column at this point as well.

The part that throws me off is the fact that the flashers work in the front, so to me the column connections are working. I am now cleaning up all grounds, lights are brighter, but still no brake or rear flasher. New flasher bulb as well.

Thanks fresh eyes always help.

 

[wildbill]

Ran into this on one they had pinched the brake wire under the bronco when they put the cross member back in. Its a place to start good luck. Bill %)

 

[Flash69]

wish i could help. Im having a lot of trouble with my sons signals and reverse lights. I still dont have them working. My brother in law is a good electrician and he is coming tomorrow to help me try and figure Lukes out. Good Luck.

 

[Mark]

If you still have the old column, plug that connector back in and see if that changes anything.
At least that can confirm or eliminate any suspicions inside the column.

 

[behemoth]

Well I pulled the wheel off and checked a few things. I have 12v to the red/black wire all the way up to the blinker switch in the column.

Can someone verify that when I step on the brakes I am putting 12v from the headlight switch to the brake switch which goes to the column. It then goes to the yellow/black and the green wires to the rear of the truck to show brake lights.

The flasher seems to be on the same path.

I have attached some portion of both wire diagrams, to clear things up a little.

Bill

 

[73stallion]

dumb question, did you check the fuse?

 

[behemoth]

I initially did not check the fuses, but today I did and they all appear to be intact. The puzzling thing is that the blinkers work front and rear, the brakes and flasher for the rear are the only thing that does not.

 

[73stallion]

okay, so how much trouble would it be to take the turn signal assembly out of your old column and put it in your new one? sounds like something in the wiring isn't matching up corectly. i know they changed the column wiring 3 times over the build reign.

i know it's gonna be a PITA, but if it makes it work correctly it may be worth the work.

 

[behemoth]

The old harness is long gone, I have a new one around here somewhere. I am trying to dig it up. Lots of junk around here.

Bill

 

[JeffBM]

I could be the blinker switch...

It has been a while since I had a similiar problem. I had voltage at the brake/blinker bulbs (for the bright filament) so I was puzzled. As it turns out, voltage only requires a very weak connection (in this case through the switch) whereas current needs a good connection (both are required to burn the bulb). I can remember that the switch inside the column was the problem, and I think I removed it and either carefully tightened the rivet that holds the sandwich together or I may have ordered a used one from a good supplier. If you do see the voltage at the socket turn on and off with someone else pressing the brake petal, try the same thing with a load light from Autoz***. They are dirt cheap and I call them a load light. It looks like a screw driver with a pointed tip, a bulb in the middle (12V of course) and a wire out the other end to ground (the clip on this end must be well grounded or it won't work either). This checks for both voltage and current. A loose connection such as this sounds like your problem to me so far.

 

[JeffBM]

I just remembered...

You can pull the steering wheel to see the blinker switch. The brake light filaments feed through the switch so as to give priority to the blinker once the brake pedal is pressed. Once you have the wheel off, mash both the brake pedal and the top of the blinker switch with your fingers to temporarily tighten the connections inside and have someone check for the lights in the rear. Try pressing in a few different areas to make the connection better in the right spot. Hope you find it.

 

[SaddleUp]

Check the plug at the firewall and make sure it is completely seated. It is a 4 prong connector that hides down between the left inner fender and the firewall making it a real PITA to get to. When the exhaust shop did my exhaust the inadvertantly pulled the plug loose and I drove that way for a week before someone flagged me down and told me about it. When I finally found it I had fun getting the thing plugged back in all of the way. It doesn't sound like this is your issue since you have signals but it would eliminate it as a possibility.