Painless Harness - No Break Lights and Weird Turn Signal Challenges

[Zachjedsmith]

Hello,

I really appreciate this community. I have a 1970 bronco with rebuilt 302, NV4500, and formerly stock wiring harness. The bronco is my wife and I's project. I was her family's primary vehicle growing up, that we are rebuilding together. By rebuilding together, I mean she tells me what she wants it to do and look like, and I follow her commands .

I have just upgraded to a painless 28 circuit harness because I was tired of chasing wiring issues but after every thing has been installed the issues remain. Below you will find what is wrong and what I have tried.

Challenges:

• Brake lights don't work - Even with a new switch and or when I use a wire to bypass the switch all together
• Most Turn Signals work at with the appropriate turn switch position - Right and Left Rear - Front passenger - Front Driver does not work but the running lights do work
• Turn Signals stop working when I pull the in dash flasher - then the hazard lights come on - If I turn off the signal (right or left) the hazards turn off
• Turn Signals stop working when I turn on the running lights and the whole system starts flashing as though the flasher is on
• Turn Signals stop working altogether with the headlights on

What I have tried:

• Replaced the hazard switch
• Replaced the brake switch
• Replaced the highlights switch
• Replaced the rear taillight bulbs
• Done a painless swap (was going to do this anyway at some point, just figured it was a good reason with these electrical challenges).
• Replaced the ignition switch
• Checked the old barrel fuse and the new modern prong fuse
• Checked and recheck the turn switch in the column - it is about 6 years old from WH

I called WH tonight and Morgan was great (thank you!) walked me through the whole system. We paid special attention to making sure the painless wires lined up with the WH turn switch wires. (Did have a question there though, does the yellow WH wire go to the yellow painless wire or does it go to the blue and yellow painless? - the horn works either way).

The turn signal switch is out of the bronco and wired up separately right now just because I was worried something was shorting out in the system.

For the other switches, I reused the factory pigtails for anything that wasn't new from painless, as I type this I am wondering if those could be the problem?

It has been a headache to say the least. The whole reason that I started this adventure is the brake lights where not working. And they still remain not working.

Thanks for the help - free 6 pack to anyone in the Fresno area is interested in swinging by.

Zach

 

[Oldtimer]

A little more information.
Any body/sheetmetal work?
Any painting been done?
First thought is ground connections.

 

[Zachjedsmith]

Thanks for the reply. No body or sheet metal work other than flares. It has a heat and sound shield spray in the tub and roll on lining underneath. Any grounds I've found I've used a wire wheel to get back to sheet metal. I did not add any grounds though. Any advice on how to check?

Zach

 

[57baja]

When you turn something on like a blinker,hazard, or a different switch and something else happens that's a bad ground or something is shorting out. Like a hot wire is touching something. You shouldn't mix a painless harness with the 50yr old wiring. I installed a painless harness and only used the original steering column wiring with supplied adapter. Everything works fine.

 

[Zachjedsmith]

I think you both are right. I pushed in my lighter and it changed how the blinker intervals (slowed it down). There has to be a short coming from somewhere. I revisited the reused pigtails at it was only the hazards switch (in-dash), the brake warning light (I think that is what this light is), and the heater wires.

I took apart the pigtail for the hazard and just plugged wire in directly to the switch and now I don't have a green dot in my gauges showing the right blinker is going off.


https://drive.google.com/file/d/1bar1eD2cT8vLSoDnZtSY8fEL62YTEkRJ/view?usp=drive_link

https://drive.google.com/file/d/12U1f4N5FiR7MPRRSrxyV758WzSdvMMIx/view?usp=drive_link

Oh, and right now I am only running the trickle charger as my only source of power, per the painless testing protocol in the painless book.

Thanks again for the help guys.

 

[BGBronco]

Definitely sounds like a ground issue. Not as many but I recently had a similar issue related to blinkers, marker lights, flashers. Couldn't figure it out and had someone check it out. As it turned out, I had a short in the wiring going to the license plate light. It wasn't listed on the same fuse so I never thought to check it out.

 

[Brush Hog]

Had similar problems when I did my painless harness. I had a bad dash to firewall ground. Once I sanded and upgraded the ground wire all issues went away.

 

[randbjorn]

I think you both are right. I pushed in my lighter and it changed how the blinker intervals (slowed it down). There has to be a short coming from somewhere. I revisited the reused pigtails at it was only the hazards switch (in-dash), the brake warning light (I think that is what this light is), and the heater wires.

I took apart the pigtail for the hazard and just plugged wire in directly to the switch and now I don't have a green dot in my gauges showing the right blinker is going off.


https://drive.google.com/file/d/1bar1eD2cT8vLSoDnZtSY8fEL62YTEkRJ/view?usp=drive_link

https://drive.google.com/file/d/12U1f4N5FiR7MPRRSrxyV758WzSdvMMIx/view?usp=drive_link

Oh, and right now I am only running the trickle charger as my only source of power, per the painless testing protocol in the painless book.

Thanks again for the help guys.

The current draw from the lighter could have an affect on the trickle charger or grounds that could then change the flasher rate so not necessarily a short there. I gotta be honest, personally I don’t like the idea of the trickle charger. I understand why, but it’s another variable. I’m not telling you to install the battery, but I might. I’ve never installed one of those harnesses before but it should be properly fused in all the right places to prevent a catastrophic failure. It sounds like you have multiple issues so you’re going to take the simplest issues and work your way from there. As you solve them, it will help with the others.

Since there’s no computer data to be concerned with, a good test light will probably be enough to figure out what going on, but it wouldn’t hurt to have a good meter too. Neither have to be fancy, but they must be in perfect working order. Nothing worse than diagnosing electrical issues with less that perfect tools. Where you ground these tools is critical. For example, if you’re testing your brake switch for power at the switch and there is none, always test a known good power source while still connected to the same ground location to make sure your ground source for your meter/light is good.

If there is a particular lamp that isn’t working when it should be, does it have voltage at the lamp or not? If yes, move to the ground for that bulb, the bulb itself, the crusty socket, etc.etc. Same with the brake lamp switch. Does it have power at the switch? If not, trace it back. If yes, trace it out from there.

I would assume the harness came with detailed schematics so that should help you narrow down the problems fairly quickly. The hazard switch and turn signal switch will be the most complicated piece of the puzzle. Hopefully they are both in good working order. Just take your time and solve one problem at a time. Eventually you’ll have all the kinks worked out.

 

[DirtDonk]

You said you did not add any grounds. I would stop right now and add some.
Do you have new battery cables? Did the negative come with a separate pigtail to connect to the body? If not, you have to create your own and run a 10 gauge wire from the negative terminal to the body.
The usual spot is one of the bolts holding the starter relay to the fender.
While you’re at it, run another 10 gauge wire from the back of the intake manifold, or one of the bell housing bolts, to the firewall.
Use an existing bolt if you can, or drill a hole for a new one, and make sure the metal is clean.
The advantage of a new one is that you can use it on the inside of the firewall as well, to ground the dash.

While you’re grounding things, with a bronco as old as yours it’s a good practice to run a jumper wire from your new body ground over to the radiator core support, to help with grounding the headlights and turn signals.

In what possible way are you using old glass tube fuses? As Justino said, you should not be mixing and matching.
Certainly you can use original pigtails and connectors, and that’s even in the Painless instructions. But to continue using the old fuse box, and it’s circuits is just crazy I think.

I would also recommend against using the trickle charger at this point.
If you are not blowing fuses, then you are probably not in danger of melting down anything.
What rating is the trickle charger? If it’s one and a half amps, it is too low. If it has an automatic, self resetting internal circuit breaker, It’s probably not helping.
If you’re going to use a battery charger use one with at least a five amp capacity and no automatic breaker.
Yes, I know the automatic breaker is for safety. But you can’t turn on something like the cigar lighter or the heater without tripping it. Especially along with the headlights and other things.
You may have to either source more powerful charger, or just bite the bullet and put the battery in.
Connect the cable and then touch the negative carefully and watch for smoke or blown fuses.
They’re probably won’t be any, but you might as well find out at some point.

But add those grounds first, and check your left front light bulb and socket to see if it’s just a simple burned out filament that’s keeping the left turn signal from working.

 

[DirtDonk]

By the way… The brake lights not working, even when jumper would lead me back to the turn signal switch again. I know it’s only six years old, but that’s a surprisingly long life for modern parts these days. You might just be chasing a fault,
I know you said you tested it, but what did you use to test it?

 

[Wild horse 75]

You really need to have a battery in the system for the charger to work correctly. The charger senses load to work. Without the load of a battery it will bounce so to speak. So that’s probably part of your problem. You don’t need a good battery just one that isn’t completely dead or for the bronco specifically. Just need the load in the circuit.

 

[Wild horse 75]

And @DirtDonk is totally right. If you didn’t add any grounds when you did the harness then you need to go back and add some.

 

[Zachjedsmith]

So helpful.

1) Adding more grounds now and cleaning up or revisiting what has already been added.

• I'll test the system with the charger and without after just to compare (been reading all your posts on other threads and 90% sure it is a grounding issue. There seem to be very little in the way of grounding on the original.
• Many of these issues where the reason why I got the painless in the first place.

2) Installed the new fusebox that came with the painless harness and got rid of all the old stuff - only reused a couple pigtails but have taken those apart now and am direct to the switch.

3) I have taken the turn switch out of the column and hard wired it into the harness following the diagram from painless and WH. Morgan and I rechecked it yesterday night.

• That said we were stuck on where the horn should go Yellow harness to yellow painless or yellow harness to blue and yellow painless?? Any help there?
• The only wire I was getting power from when tested was the blue flasher switch. But sometimes it would trip the horn and sometimes just the flasher (grounding issue).

I'll circle back after I try some stuff and let folks know how it goes.

Thanks guys pretty great community here.

Zach

 

[Oldtimer]

I addeda ground junction block.
Ran a 10 gauge wire from battery to junction block.
Than ran ground wires from juntion block to:

• Starter relay mounting bolt,
• Voltage regulator mounting bolt,
• Duraspark II mounting bolt,
• Core support,
• Headlight relay harness ground,
• And a ground wire ran to dash, for aux circuits that have been added in the last 50 years.

Also for testing, a 15 foot wire with alligator clip on each end, clamp one on battery ground, use other end to create temporary ground at turnsignal lamp fixtures.

 

[DirtDonk]

Since your ‘70 model did not use a horn relay, and the Painless harness does, double check the Painless instructions for hooking up the horn wires.
I don’t have them in front of me, so can’t verify anything at the moment.

 

[Zachjedsmith]

Figured it out!

Turned out to be a bad fuse . After all that. It looked fine but on further examination, power was not traveling through it.

I can say now my grounds are much more on point though!

Thanks for your help everyone.

Zach

 

[DirtDonk]

This is as good an argument for blow-and-glow fuses as there is.

 

[Wild horse 75]

This is as good an argument for blow-and-glow fuses as there is.

Very true. When I test fuses I’ve always used a test light. Seen way too many fuses blown right at the edge where you can’t visually see it and that causes nothing but headaches.