Lost brake lights - but only one side.

[71Beeper]

On my 71 Runner, while I was putting it together I tested all the circuits for the tail lights & everything was good.
Just by coincidence while I was pumping the brake pedal with the car in the garage I glanced in the rearview mirror to see if the tail lights were coming on & they were not.

At first I thought maybe the key had to be in the on position for the brake lights to work (my wife's Austin Mini is that way) but I knew that was not the case.
So tonight I started in the trunk when the rear harness plugs in. Since the battery is in the trunk, I supplied full 12V power to each prong on the harness plug and each light was working just fine - even the license plate light works.
So I plug that harness back in and go to the drivers kick panel where the next plug is.
Unplug it and proceed to run full 12V power thru the rearward harness to confirm it's not the wires themselves.
No issues - as I applied 12V power to each wire I got lights.
First the black wire with yellow tracer (I think) and everything lights up - this is obviously the nigh time lights.

Next I power the green wire and voila - drivers side.

Next I power the brown wire and the passenger side lights up.

lastly I power the violet wire and I get the reverse lights.

So now I look at the plug that coming from the main harness side.

With no key in the ignition, my test light shows the 2 pink wires (joined together) having power.
Looking on the plug going to the back of the car those 2 pink wires connect into a grey wire.

Since I didn't see that grey wire in the wire harness plug for the tail lights am I safe to assume that is for the fuel sending unit?
So, my dilemma is - with the key on I get no drivers side signal but I do get the passenger side one.

Here's the weird part, when I tried the 4 ways, the fronts worked great but the rear drivers side marker bulb was flashing as was my dash cluster night time lights!
Both front side markers were flashing but dim.
Sounds like something was back feeding to the wrong place.

Any of you guys had similar experiences?

 

[kiwigtx]

Turn signal switch is either dirty or damaged.

 

[dadsbee]

Wiggle the ts switch back and forth..

 

[Charles Cook]

Turn signal switch. I had the same issue with my 68.

 

[hunt2elk]

Turn signal switch would be the first thing to check. Had a 69 RR conv that had the exact same issue.

 

[71Beeper]

Me like many others here installed a new re-pop switch.
What exactly goes wrong that causes that many issues?
Is there anything I can do to the replacement so it too doesn't fuk up like the current one that's on the car?

 

[kiwigtx]

Turn signal switch. I had the same issue with my 68.

As did I with the '70 GTX.

 

[kiwigtx]

Wiggle the ts switch back and forth..

...or spit on that thang. (maybe not)

A little contact cleaner sprayed on the terminal block of the turn-signal switch inside the steering column may help prove the theory before dis-assembly.
Not too much or you might damage stuff.
Probably gummed up with dust on the little bit of grease over the years.

 

[71Beeper]

Kiwi - normally I would agree with you but this is a new re-pop switch I installed.

It hasn't had a chance to accumulate anything (I hope.)

I think I'm going to see if I can find the one I took out as it appears to be an original one.

 

[71Beeper]

So I checked my stash and I actually have 2 factory switches.
I have this one but the 4 way portion is broke off.

And I have this one ,but it has a broken cancel cam.

Both have this tag on it.

I'll use the one with the broke off 4 way switch but first I broke out the JB Weld for plastic and glued the 4 way back into place.

Here's the re-pop one coming out.

Put the other one in and ....... still no worky.

No brake lights or signals or 4 ways.
Cruise lights and maker lights all work.

I checked all my fuses and there's power on both side of all the fuses (with key on).
Even the brake switch has power at both connections when the brake is applied.

At least now I have no weird back feeding anywhere.

The only thing I didn't change out is the flashers - that will be next to try....

 

[kiwigtx]

So I checked my stash and I actually have 2 factory switches.
I have this one but the 4 way portion is broke off.
View attachment 1730189
And I have this one ,but it has a broken cancel cam.
View attachment 1730190
Both have this tag on it.
View attachment 1730191View attachment 1730192
I'll use the one with the broke off 4 way switch but first I broke out the JB Weld for plastic and glued the 4 way back into place.
View attachment 1730193View attachment 1730194
Here's the re-pop one coming out.
View attachment 1730195
Put the other one in and ....... still no worky.

No brake lights or signals or 4 ways.
Cruise lights and maker lights all work.

I checked all my fuses and there's power on both side of all the fuses (with key on).
Even the brake switch has power at both connections when the brake is applied.

At least now I have no weird back feeding anywhere.

The only thing I didn't change out is the flashers - that will be next to try....

How is the condition of the big flat connector lower down the column? I have seen those cooked up also.

 

[kiwigtx]

...and the turn signal cancelling cam area is where you need to look.

 

[Nacho-RT74]

Ok lets go step by step.

As you found, brown and dark green are each side (for blinkers and brakes), violet is backup, black is parking. Those are the same from end to end.

On kick panel plug we add pink which is for the deck lid light (constant positive which I didn’t remember becomes gray on side harness, socket is a tilt switch handling ground) and blue is fuel sender. On underdash harness the violet wire running to rear becomes white traced coming from bulkhead/NSS.

So if you feed the same wires you did straight at tail lights plug but at kick panel plug, will light up the same.

On steering column plug factory colors are for inputs:

-White, coming from brake pedal switch to give brakes.
-Red from turning signal flasher
-Pink from hazzard flasher.

Rest are:
-dark green, rear left
-light green, front left (and cluster)
-brown, rear right
-tan, front right (and cluster)
-black, horn switch


Next I can see, one the factory turning switches is actually a later factory replacement. Originals and earlier replacements are still with a bearing on stud for the horn switch track. The one with the extra 3 ways pigtail is for the cornering lights used on C bodies and typically offered as a generic later replacements by MP and these are without the bearing, but just a spring loaded plain stud.

The first switch you shown on reply 10 is the turning swicth made of a material called UNOBTAINABLE (LOL). If in working order you have a big bucks switch there. Which is also installed on a wrong column collar. That collar is for the wider hazzard knob used since lates 71s and 72 and laters. Earliers 71s and all 70s used a diff column collar and accomodattes that thin hazzard knob switch.

About sidemarkers dimming. If dimming with parkings off (not blinking), could be a ground issue. If dimming with parkings on, could be just a matter of decay on voltage with engine off and everything being supplied by just the batt begining to get discharged.

Now about how the switch works:

On rest position the turning switch keeps in contact the white with dark green and brown for brake lights. So once you give brakes, the normally closed position on the TS will allow to feed just brakes.

When you set left turning, the red wire coming from turning flasher feeds both green (light and dark) wires for let turning. The flasher will make blink the bulbs as soon it gets the bulb loads running throught. White keeps in contact with brown to allow the brakes to light up just on rear right side

When you set right turning, is just right the oposite… red with brown and tan, while green keeps closed with white.

When you set hazzards, all 4 corners changes to be feeded from the pink wire coming from hazzard flasher. Brake lights are completely disabled. (Up to 69 the brakes could be activated thought still with hazzards).

You can test flashers just jumping out wires accordingly at plug. Red with either both greens or tan/brown will activate turning and Pink with all 4 corners. Once these tests made, you will trace down where is the fail. Brakes of course between white and dark green and brown.

 

[Nacho-RT74]

On a side note, sometime ago a friend of mine got that replacement switch (in Venezuela we got same units) and something was not working. Can’t recall what it was. Since replacement colors are not the factory ones we had to trace wire by wire from plug up to rivets on switch compairing with the factory one and found two wires turned around at rivets.

 

[Nacho-RT74]

...and the turn signal cancelling cam area is where you need to look.

This is critical for the brakes light work. In rest position both rear circuits must be closed with the brakes pedal switch.

 

[71Beeper]

Many many thanks Nacho!
It gives me something to go by.
I'll post my results.

 

[71Beeper]

Well boys - problem solved.

It was 2 things.
First that chineaseum turn switch - there's nothing wrong with it other than the plug that goes into the main harness is a little tight.
The factory one I put on the car yesterday does not work....

The second thing which contributed to the back feeding.......the front passenger signal housing.
I lost the grounding between the bulb socket housing and the casting - that caused the power to go wherever it could which was the side marker lights & dash lights.

With the front signal housing I'm gonna try and McGiver it so there is a contact.
If not, I have a 1972 housing that I will have to change the plug out.

And re-install the chineaseum switch back in the car.

It's a relief to know what the issue was - now to get it fixed.
Thanks for all that replied - this is a great forum for us Mopar guys!

 

[Nacho-RT74]

I had same ground issue on one of my front parking lights. What I did is smash the socket lip itself with a screwdriver and a hammer against the housing on a couple of spots to get it back tight.

 

[71Beeper]

I will give that a try Nacho.

 

[72RoadrunnerGTX]

Do I understand you believe the grounding issue at the front turn signal housing has resolved the described left rear brake issue? One stop light inop with both rear functioning turn signals can only be a contact problem within the turn signal switch. The turn signal switch operation does not involve any grounding anywhere. Sounds to me you have a couple of bad T/S switches. Those cheap repo T/S switches are junk, better off to find an NOS OE switch with a roller horn contact. The basic switch was used across many platforms and years, the correct NOS switch may be spendy but you can modify less expensive switches for other applications to work if you can swap out the connector.