O.K. This is my final question regarding the problem that I am having getting the rear lights to work on my 71 custom.....here it goes...If the turn signal switch is bad, would the signal work on one side, and not the other?
If so, would it keep the brake lights from working...checked bulbs, grounds,etc., but still no workie....this is my final question about this, I promise....I may just push her in a ditch...lol....Nomadic

 

Hey Nomadic
I'm having a similar problem as well, but not on my truck. The truck works correctly in every way but I can't seem to get the lights on my old boat trailer to work properly. I have a 70 CS with the wiring harness (I posted about this yesterday). The trailer has just wires that I plug into the harness. At one point I could make the running lights work, but when you hit the brakes, there was nothing on the trailer. When I got the brake lite to go on the trailer (standing there by myself looking back) it worked but I discovered later that it was lighting up on one side and going dark (running lite, brake lite) on the other. I don't think it's your signal switch, but rather a botched job of re-wiring done at some point before you had your truck. Someone may have spliced in wires somewhere that don't have proper color coding. They might be right at the beginning point and the end point, but somewhere in the middle they may be crossed. That is the problem I'm having with this old boat trailer. The harness worked correctly for the camper I had (and junked). The lights all worked correctly and were in sync with the truck. With this new trailer, I'm doing trial and error to get it working right. In other words, my problem is everythings works front to back on truck, but after that it's screwed up; your problem is that it's screwed up from front to back on truck. Somewhere you have a wire out of sequence or a bad connection. You would still get a correct reading as far as grounded or powered, but it's probably not getting powered at the correct time. Does this make sense or at least sound reasonable to anyone. Wiring problems suck because you may have a broken wire that, when you pull it straight to check it, it makes connection, but when you fold it back to where it's been for decades on these trucks, the connection breaks again. JMO, but go back over the wires where they show and look for splices. It's unlikely someone put a splice in a really inaccessible place (it would have been too difficult). Don't shove that truck in a ditch!

 

I'm going to say if one side turn does not work, then the possibility of the brake light NOT working is also good. One side may work, and the other not. If the contacts in the switch itself are broken, then the brake light and turn signal on that side may not work. It's a guessing game until you get the switch out and look at it. If you could locate a wiring diagram of the switch you could test each lead to see if one is broken inside the switch.

I guess the easiest thing to do is pull the steering wheel and check the condition of the switch. It might be noticeable that it's damaged, maybe not. I've lost track of this things you may have done so far. I've been away for awhile and not read up all the posts.

There are only FOUR wires to the rear of the truck. Relatively simple to trace which is which. Knight70F250, your trailer is now not working, and the other did then it seems you may have some wiring issues on it. Make sure you have a GOOD ground to start with. If that is weak...it will back feed or dim other lights as it tries to find a ground. The trailer only needs 4 wires, each brakelight/turn(total of 2), running lights and a groundwire.

Are you using a regular plug on truck and trailer?? or just twisting them together right now to find something that works? Just make sure your ground is good first, then work on the rest.

 

yes if one side of switch is bad it will cause your problem just like it did on my 72 custom i got a steerinf coulmn out of a 79 f-100 just rewierd it to my plug and all my light's went to working ....happy happy.....about damn time they worked......

 

Nomadic,

I tried emailing you, couldn't. Shoot me one. I'm sure I have something that can help.

Bryan

 

Freightrain,
Thanks for your reply. I didn't mean to step into nomadic's post but so far no one has replied to mine. I have been plugging wires from my boat trailer into the camper harness on my truck. The wiring on the trailer is very simple. I was just looking to see if anyone knew the color-coding of the wires going INTO the harness on the truck. (Which wire controls brakes, left turn signal, right, running lights?) I need to extend the wiring on the trailer to meet up to the wiring harness on truck which comes up behind cab (not bed). The trailer just has a bunch of loose wires (no harness) and I would just replace all of them with longer ones. In other words, I can tell which wire comes off trailer for specific function, which truck wire do I hook up to? Thanks

 

Nomadic,
Yes I Believe The Turn Switch Could Cause Both Problems
You Know What They Say About Elec. Problems,
All Day To Find The Problem And Ten Minutes To Fix It. Ha Ha
Good Luck

 

dude that is EXACTLY what my problem was just replace the turn signal switch in the steering column and everything will start working again. atleast it worked for me

Signed,
The Don

 

I have the same problem sometimes my signals work and the dont but my brake lights never work any more, but my tail light work when I turn them on and my revers lights also work, could it be related to the turn signal switch?

 

Yes, it can. It sounds like a worn turn signal switch.

Also check the Brake light switch conected to the brake pedal. They liked breaking off on my '73.

 

Knight.....trailer wiring is a simple fix. Buy a new lead from Azone or such. You can buy long leads that have plugs on each end. Cut the end you need.

Typical wiring: Green RIGHT and Yellow LEFT turn/brake for each side, White is ground, Brown is running lights. Go to Marksrv.com to see the typical wiring for the plugs. They have a handy diagram for wiring.

As for wiring in truck, no idea. I know that brown is running lights out back. Not sure if the other colors match what I mentioned above or not? Take a test light/or meter and activate blinkers to find out which one does what. Simple since there is only FOUR wires to deal with.

I would probably just buy the new lead wires and run them to the back to plug in at the bumper. Seems much easier to deal with than running them up thru the bed to front. Just my opinion.

Let me know if you need any other help. I'll see what I can do.

 

I have an old style turn signal switch in 74, both turn signals work, but the right side brake light doesn't untill you push the leaver to the dash just slightly.

 

My '69 is just now acting up also. I realized the other day when buddy told me RR brake light was not working. Hmmmm, wiggled the turn signal switch and it worked again. Seems the switch is starting to fail, or just needs some attention.

Might pop off the steering wheel and do some lube work.

 

I am having difficulty finding a new turn signal switch for my 71...consequently I don't drive it much at all.....The local Autozone said that they did not show a listing for them...of course, have a couple of other local possiblities as well...plus a couple of catalogs...but...been putting it on the back burner....I think I read somewhere in the forum, that you did not necesarily have to have a wheel puller...that the wheel is on a spleen...and could be, more or less tapped off...is that correct...?.......My neighbor told me the other day that I spend more time washing and waxing the old custom than I do driving it....Anyway, when I do get the lights hooked up....It will be really shiny, huh....lol....!

 

I don't know if your trying to keep the truck all original or not, but before I got my truck from my Grandpa, he had gotten tired of the blinker switches messing up (engaging on their own, not working sometimes, causing these problems, ect.) so he got an aftermarket unit that has an aluminum strap/clamp around the steering column holding it in the original location. I didn't even notice it didn't belong until he showed me. It has a nice little chrome handle, and a chrome pull out tab for the hazards. All the wires are ran up under the column in a wire loom. The unit says SIGNALFLARE on it. Good luck.
Brandon