Brake light problems still

[71Ford100]

So I still don't have any brake lights or flashers and this is what I have done. Replaced the fuse box (it was junk), replaced the turn signal cam with a good used one, and checked the bulbs and stuff to make sure they were good. Anything else that would cause these not to work.

[seattle67]

Ok Lance,
This is going to be painful, but to trouble shoot over the internet we will need to do this in a methodical manner. You're going to need either a test light or a multimeter to do this.

We just have to follow the path. I'm going to go step by step, all the way from your fuse box to your brake lights. But, if at any one of these points you lose power, then that is where I would expect you'll find the problem.

With one lead of your test light or meter connected to ground, put your other lead to the red-white stripe wire that is connected to your fuse box. It should have 12 vdc + at all times. If you don't have power there let me know and we will go from there. But for now, I'm going to assume you have power there.

The red-white stripe wire goes to your emergency flasher, check and see if you have 12 vdc + at that connector. Next step.

There is a red wire on the emergency flasher, this wire supplys power to your brake switch. Find the red wire on your brake switch and check to see if you have power there. Next step.

The other wire on your brake switch is red-black stripe, there shouldn't be power on that wire until you push on the brake pedal. Go ahead and push on the brake pedal and then see if you have power on the red-black stripe wire. Next.

That red-black stripe wire goes to a connector at your steering column, you could unplug that connector and see, with the brake pedal pushed in, if you have power there. Next

Ok, up until now we have been chasing a single path, but this path gets split into two paths in your turn signal switch. We don't need to get all technical here or anything, just trust me when I say it's all voodoo! I would explain it but then you would have to join the electrical union and learn the secret hand shake and sacrifice a virgin, when all we really want to do is fix your truck! So, moving on...

Power from your brake light switch goes into your steering column through the red-black stripe wire, it comes back out on a green wire for your passenger side brake light and a yellow-black stripe wire for the drivers side brake light. Be aware that between the connector at your steering column and the brake lights themselves, those two wires go through about two to three connectors, any one of which could be a point of failure.

Anyway, just follow that path Lance and look for the point that you lose power, don't randomly jump around, good trouble shooters are methodical in their technique.
Just worry about the brake lights for the moment and don't worry about the flashers. Odds are fixing one will fix both problems.

I wish I was there to give you a hand, we could have this fixed in no time.

Good luck!

[Underdog97]

Also check your grounds . I"ve also seen turn signal switches just not work period as the contacts in them are worn out or not making good enough contact. I've replaced the cancelling cams on many a switch and have found that it's a 50/50 chance of the switch working properly, especially with a used cam! I'd go with Seattle 67's advice on troubleshooting it as from what I read he has the circuitry down pat. The one question I would have is the year of the truck you're working on as it states on the bottom of your posts that you have several. Ford did change the colors of some of the wies thru the 67 to 72 trucks. The 67's can be a nightmare at times.

[19674x4]

thats a good write up dan, i think ill print that for future reference. im having the same troubles

[seattle67]

thats a good write up dan, i think ill print that for future reference. im having the same troubles

Thanks! Keep in mind though, as underdog mentioned, the color codes are slightly different on a 67, the yellow-black stripe wire going to the driver side brake light on a 71 is a solid yellow on the 67's.

And Lance, underdog is absolutely correct in mentioning to check the ground connections at your brake lights. Thanks underdog!

[flyboy2610]

Have you checked the brake light switch on the brake pedal? Make sure both wires are on it tightly. There should be continuity through the switch when the pedal is pushed, and not when it is released.

[71Ford100]

Thats an awesome write-up Seattle....it should become a tutorial or something! I'm going to trace everything this evening.

[Thunderfoot]

Ok, up until now we have been chasing a single path, but this path gets split into two paths in your turn signal switch. We don't need to get all technical here or anything, just trust me when I say it's all voodoo! I would explain it but then you would have to join the electrical union and learn the secret hand shake and sacrifice a virgin, when all we really want to do is fix your truck! So, moving on...

ROFLMAO


Nice write up Dan!

[kaptnkaos]

Good job here Dan...

I copied and edited it to add to the electrical folder I have been putting together since starting on my truck...

Thanks again for all your help...

KaptnKA S