47-59 i give up. i need help.

[evilokc]

i have a 53 chevy with an EZ wiring harness. i didnt install the wiring which was a big mistake. you cant trust anyone anymore. the issue is the brake lights. they have been working for years and now they dont. the lights themselves are LED with the tail ,brake, and turn all using the same leds. the tail lights still light up. the turn signals still work but when i hit the brake nothing happens. my first thought was brake switch. i tested it with a power light and its good. not believeing it i replaced it anyway with a new one that tested good but still no brake lights. at the rear light plug there are two wires per side. one for power the other for turn signal. with the tail lights on the power wire has power. with the turn signal on they both have power. push the brake and both wires lose power. the tech line said to check the wires from the steering column to the brake switch and its good. then they said check brake switch and its good. then they said if both of those are good then you have brake lights. i dont though. im out of ideas. ive started pulling the two wires out of the loom the whole length of the harness to see if i can find anything. since they have power individually i cant imagine what i would find? the only thing i can think to do that i havent is to run two new wires from the fuse panel to the brake light plug to see what happens. again since eveything has power i dont know what im expecting to be different. ideas would be greatly appreciated. this has gone on far to long.

[jweb]

Have you had the led lights the whole time? You need a “no load flasher” for leds.

Do your park lights work? Maybe your headlight switch

I have an EZ harness and led lights in my 51. I had trouble with my taillights and it was a ground issue.

Let me know if there is anything I can check or compare on my truck that may help.

[_Ogre]

a little info is needed. what column? and what turn signal switch? does it have hazard flasher function? half ton or bigger? don't be pulling wires out of the wire loom yet, chances are the wiring is fine. first thing is to check grounds, a bad or partial ground will just pop-up and cause headaches. do you have led replacement bulbs or led lights with 2 wires.

other than the same housing, the tail light and stop/turn light are separate. tail lights and front running lights get power from the headlight switch. stop/turn lights are the same circuit and get power thru the turn signal switch. the turn signal bulb is the same as the stop light bulb. same bulb, same wire.

stop/turn wiring is simple, 7 wires: 3 hot in (turn flasher, hazard flasher and brake switch) and 4 wires out to each corner of the truck. the turn signal switch is the confusing part, cuz it combines the brake power and the turn flasher power, depending on what your using

this is an early bronco turn signal wiring and switch. very typical of any pre computer car with hazard flasher, this is what ez wire will look like. i chose this cuz it shows the internal function of the switch. if your truck has signal-stat it will be the same. take a long look at how the turn signal switch runs power thru to each corner.





get some answers and report back

[mr48chev]

Originally Posted by evilokc

i have a 53 chevy with an EZ wiring harness. i didnt install the wiring which was a big mistake. you cant trust anyone anymore. the issue is the brake lights. they have been working for years and now they dont.

the lights themselves are LED with the tail ,brake, and turn all using the same leds. the tail lights still light up. the turn signals still work but when i hit the brake nothing happens. my first thought was brake switch. i tested it with a power light and its good. not believeing it i replaced it anyway with a new one that tested good but still no brake lights.

at the rear light plug there are two wires per side. one for power the other for turn signal.

with the tail lights on the power wire has power. with the turn signal on they both have power.

push the brake and both wires lose power. the tech line said to check the wires from the steering column to the brake switch and its good. then they said check brake switch and its good. then they said if both of those are good then you have brake lights

. i dont though. im out of ideas. ive started pulling the two wires out of the loom the whole length of the harness to see if i can find anything. since they have power individually i cant imagine what i would find? the only thing i can think to do that i havent is to run two new wires from the fuse panel to the brake light plug to see what happens. again since eveything has power i dont know what im expecting to be different. ideas would be greatly appreciated. this has gone on far to long.

Sorry but I had to spread it out somewhat to sort it out.

Power to the brake light switch and power from the brake light switch = no problem with fuse or brake light switch if the power goes on and off when you move the pedal. Move on to the next point.

Tail lights don't count as long as they work. If they go on and off with the switch that circuit should be good. The issue that they go out when you hit the brake may be ground or a wire crossed.

Stop and turn are on the same circuit (s) meaning when you press the brake pedal power goes from the brake light switch though the turn signal switch and through a pair of contacts that connect both turn signal wires to the brake light switch. That is how power gets to the stop/turn lights when you don't have separate brake lights.

l have a feeling that it is the turn signal switch it's self and not the rest of the wiring.

[dsraven]

check power at the light, each circuit individually no light attached. check the brake circuit with the rest of the lights off, then with them on, one added circuit turned on at a time. if there is a plug at the light, disconnect the plug and check the vehicle side of the plug on all circuits including the ground circuit. don't just use a resistance checker/ohm meter for the ground, do as best as you can for a load test ( like use something that is gonna use some juice) because a single strand of wire the size of a hair will show good continuity but will not necessarily pass enough juice to light the bulbs all at the same time.
if all good then test the actual light side of things. possibly a bad connection inside the light can cause backfeeding through another circuit because, say, it has no ground connection in the light anymore. if that seems good, plug in or wire up an old fashioned filament style tail light and see what happens with all the circuits. sometimes a bad ground inside a light will mean power goes into the light like normal, but since the bulb has no ground the power goes through the filament to ground, no ground so it goes back into the other filament connected to the same bulb exterior-so same ground on the bulb body-and then it follows that othr circuit until it finds a ground somewhere else/ like the signal indicator bulb on the dash cluster. sometimes simply turning the lights on and using a test lead to supply a ground to the light bulb will give you an instant fix. then you know it was a ground problem.
I recommend starting at the light and working forward. if there is a trailer plug check that as well. unplug it if possible and then test the lights to see if that fixed the problem.

[mr48chev]

What exact turn signal switch do you have in the truck? As in what and who's column or do you have the aftermarket switch like Ogre showed or a different aftermarket fasten to the column switch?

Most aftermarket columns use a GM Delco turn signal switch or a replacement for one.

What I am showing here is an image of a pigtail that connects a turn signal switch with a flat connector to a vehicle with a rounded connector. What you are interested is the color of the wires and what each wire connects to.

What I want you to do is take a jumper wire and put power to the stop light plug then take your test light with power on to that plug and check the rear turn/stop light plugs for power.
Meaning that rather than doing random checks I want you to start checking systematically from the power supply to the stop light switch back one step at a time.

[dsraven]

if you could post a pic of the lights and column/wiring at both ends that may help. like advised a few posts back, don't go digging into the harness quite yet as that is most likely not going to be the issue unless there is obvious mechanical damage. also try really hard to not use a pokey tipped tool to dig/probe into the wire sheath as that is just another wiring issue you will have to deal with later when it corrodes and doesn't work properly.
if you have 2 wires per side then one is tail and the other is brake and turn. what we always take for granted is the other line-ground. power goes in but has to come back somehow or the lights won't work because it is an incomplete circuit. we have to believe that the system has functioned properly at some point. personally i don't have much faith in the "complete LED light assembly" from offshore. too many I have seen have suspect grounds inside the light. sure, there is power getting to the bulbs but it can't find a way back to complete the circuit because of a faulty ground circuit so the light doesn't work. that is why I suggested in the earlier post to check for power and ground at the rear of the truck at the actual vehicle side of the light wiring with the light unplugged. if you have tail light power with that circuit turned on, and you also have turn signals with those circuits turned on, and you have a brake light that works when the brakes are turned on, then turn on the signals and step on the brakes to see if that works properly-it should be a solid brake light on one side with a signal light on the other side for whichever way the switch is moved to. if that is all working properly with your test light and no truck lights connected at the rear then the problem would appear to be inside the LED lights. if both sides are involved and they are doing the same thing then I would check to see if there is also a common ground between those 2 lights. if the lights use the body of the light as a ground then check the ground system by simply grounding the light body with a test lead or booster cable-to a good ground on the frame. if the lights start to work properly with the test lead grounding the light body then it would seem that the light housing is not grounded, or the body panel the light is attached to is not grounded. don't assume that since the body/box is bolted to the frame that there will automatically be a good ground there. personally I always try to run a dedicated ground circuit to the frame for each light along with a star washer under that connection to ground. nice shiny bare steel for the ground surface, tighten up the connection and then seal that connection with paint or some form of sealer. personally I use the brown non hardening aviation form a gasket because it forms a weather tight seal but doesn't get hard and crack over time. the battery negative lead should be ran with large cable to the frame and the engine block. it should also have smaller ground wires that run to the body parts-one to the cab, the rad support, hood, the box etc and these leads can be taken from the frame to keep the battery area looking less crowded. this is because otherwise the electrical accy's bolted onto those body parts are usually all relying on the body parts touching each other with bare metal to bare metal in order to get a ground and they don't have a dedicated ground wire on them.
in my box of electrical stuff I have a big trailer light that is used on semi trucks/trailers. it has regular old fashioned filament bulbs in it because they take a little more power than LED bulbs. the lights have a pigtail on then that has a ground clamp and a couple of cheap crimp on insulated plugs for the tail and stop/turn light leads. I use this to test lights because it is large so it gives off enough light for me to see from the cab when I am stepping on the brakes or switching on/off tail lights etc and because it draws enough power to stress a poor connection that an LED light may not because the LED's draw less. it is also pretty durable and the pigtail simply unplugs so it takes less room in the tool box after. this is really handy for testing this type of scenario.
light
https://www.amazon.ca/Grote-52772-To...90336136&psc=1

pigtail
https://recstuff.com/trailer-accesso...ree-connector/

ground clip, I also extend the ground wire from the pigtail so I have more possibilities for a good dedicated ground when testing because sometimes the light is a distance from the dedicated ground of the vehicle frame. notice the clip has pretty aggressive teeth on the contact surface to break through surface rust on the vehicle frame
https://www.digikey.ca/en/products/d...saAo7rEALw_wcB

unplug both rear lights and check with something like this to see what you have back there on each wire. then, if those circuits test all good, clip your test light ground onto the existing light's ground (be it the light housing or possibly inside the light-where ever the light is getting it's ground from) and supply power to one of the other wires in the pigtail from, say, your tail light wire that you just checked. the test light should light up (with the tail lights turned on of course) because it is getting power from the tail light circuit that you just tested and found to be fine, and it is getting a ground from the light housing (or where ever it is wired to be grounded to originally) like it would normally. if it doesn't light up then you have a bad ground on the light. if you are unsure then simply unclip the ground from the light housing and touch a known good ground, the test light should light up. this is the most common light problem I have found from years working in the trade, aside from mechanical damage or a burnt out light. bad grounds then poor bulb connections inside a light, then poor plug connections usually with corrosion, then previous repairs using crimp connectors that are not crimped well and/or not insulated against weather so they corrode. not usually the harness unless there is some sort of mechanical damage
if your test for power at the rear yields no brake light power, then look at the outputs from the signal switch. brake light power comes from the brake switch and goes into the signal switch where it gets sent down the circuit according to the position of the signal light switch. if you have output from the brake light switch with the brakes applied, all the way back to the input of the signal switch at the base of the column, then it would seem that there is either a problem in the signal switch or else the brake light wire was/is cut or otherwise disconnected from the signal switch inside the column possibly. otherwise the problem would seem to be internal to the signal switch.

man, I hope all that made sense.
keep us posted and, like said, post some pics

[dsraven]

quote:
at the rear light plug there are two wires per side. one for power the other for turn signal. with the tail lights on the power wire has power. with the turn signal on they both have power. push the brake and both wires lose power.
---------------
can you explain this a bit? do you mean the tail light wires are hot on both sides of the truck when the tail lights are called for-like they should be, and then the tail lights were turned off to check the signals next but when the signals are turned on both the signal wires and the tail light wires are hot on both sides of the truck? did you mean the tail lights were still on and hot and then when you turn the signals on then both the tail and signal wires are hot on both sides of the truck at the same time? then when you step on the brakes they all go dead with no power to any wire? is this from a test light with an independent dedicated ground attached to the truck frame?
have you ever checked the front lights to ensure the original wiring didn't get mixed up so the front signals are actually wired up to the switch where the rear signals are supposed to be? do the front signals work like brake lights when the brakes and signals are both called for? I have seen that done before. not necessarily with your symptoms.
can you give us a play by play on each circuit

tail lights on only
-power to tail light wire on right side
-power to tail light wire on left side
-no power to signal/brake wire on either side

right signal light on only
-power to right signal wire
-no power to left signal wire
-no power to tail light wire on either side

left signal light on only
-power to left signal wire
-no power to right signal wire
-no power to tail light wire on either side

brake lights on only
-power to right signal/brake wire
-power to left signal brake wire
-no power to tail light wire on either side

tail lights on and brake lights called for
-power to tail light wire on both sides
-power to signal/brake wire on both sides when brakes on

[dsraven]

without seeing the wiring for the signal switch etc I don't know if this is gonna help at all, but all the older GM's columns have use pretty much the same color codes off the column plug.

Black Horn

Light blue Left front turn signal

Dark blue Right front turn signal

Brown comes from the Hazard flasher

Purple comes from Turn signal flasher but will be powered only with the key on

Yellow Left rear stop light and turn signal

Dark Green Right rear stop light and turn signal

White comes from the Stop light switch and that circuit should be hot at all times. it will only show power to that wire when the brakes are called for though

once it is transferred to the harness that heads out back you may find the tail light wire is brown, the right turn is green, the left turn is yellow. there may or may not be a back up wire mixed in as well. there may or may not be a ground wire mixed in and there may be another wire mixed in to use for a high mount brake light
once you have checked out the rear and found it to be good or repaired any issues with grounds etc, if you still have problems start at the front where the signal switch is. first jot down the colors used at the rear for the different circuits and then head up front under the dash, unplug the signal switch and use a test lead to power the different circuits on the body side of that switch (not the column side). this will test what wire has been connected to what circuit that goes to the rear. an inline fuse if good to have here wired into your test lead so you don't touch the wrong wire and weld something together, lol. I also use a small cotter pin or a craft T pin (https://www.amazon.ca/Stainless-Stee...73258617&psc=1)
as a probe to push into the wiring block so I know there is connection to that one circuit only. another tool I have in my wiring repair box is an audible alert that I poached from a donor vehicle and it can be used out back on the wires so when I power up the wire for a circuit I know if it came on while I'm stuffed up under the dash. connect the buzzer to a circuit, then go power that circuit and listen for the buzzer. yes, then you need to get out and connect the buzzer to the next circuit

here is a pretty good turn signal and tail light wiring thread that explains a few things about the different possibilities for different signal light switches

https://www.jalopyjournal.com/forum/...how-to.869492/

[MiraclePieCo]

Brake lights are typically just both L&R turn signals applied at once. The problem can likely be found in your turn signal circuit.

[gigamanx]

I went through similar pains with my truck wiring up the all in one brake lights on the rear. They were also LED. Thankfully, my issue started from the beginning but what I found was the wires were grounding out inside the steering column. To fix it, I had to replace the turn signal harness doohicky in the column and run a new wire harness with the GM adapter on the end. It was a huge pain in the butt, but fixed my brake situation. Like you, I kept assuming I did something wrong because the column was brand new, the lights were brand new, it must be me!

[mr48chev]

Turn signal harnesses aren't all that hard to change. I usually fasten a wire to the plug on the harness before I pull it out tying the plug to the harness keeping it straight and pull the length of wire though the housing, then tie the wire to the new harness's plug in a similar fashion and pull it back through. That has saved hours of trying to poke the harness down though the housing.

I guess I am going to have start writing things down that I intend to do as I was going to go out and snag one of my old columns and do a little demo on checking continuity in the brake light circuit in the turn signal switch.

[dsraven]

hey evil, did you figure it out?

[mr48chev]

Inquiring minds want to know.

[dsraven]

I do what mr48 does but snap a pic of the plug, or draw a diagram of what wire goes where first, then check the colors against the new part if replacement is the plan. then remove the plug and pull the wires up through the column with the mechanics wire. the mechanics wire pulls the new part back through the column like mr48 describes. assemble the plug on the end when done. it's easy to get the individual wires out of the plug, just look for the barb on the wire terminals where they sit in the plastic, push the barb down to release the wire from the terminal and gently pull the wire out of the block.

[mr48chev]

I've tried that but found that I can snake the wires through with the piece of mig wire tied to them holding the plug 90 degrees to the wires in the harness all too easy. I've probably done 30 of them over the years. When you do these things for a living every day you learn tricks that save you time and make you money.

[dsraven]

That's usually what I do too but sometimes a tilt column gets ugly.

[mr48chev]

Tilts aren't that bad, you just have to remember to put everything in facing so that the switch drops right in place, there is no turning that ribbon wire over once you have it in the column.

[1project2many]

I've tried that but found that I can snake the wires through with the piece of mig wire tied to them holding the plug 90 degrees to the wires in the harness all too easy. I've probably done 30 of them over the years. When you do these things for a living every day you learn tricks that save you time and make you money.

^^^
100% agree.

Worst one I did was in a quonset hut in MT while it was 30 below. Holy farking freezeness. The bolts holding the tilt mechanism to the column had fallen out so the truck couldn't be started or steered. Usually no big deal. But not so when sitting in a cold truck with a 25 watt light bulb in an aluminum shielded light for heat. Had to wrap the harness inside the shield so it would get warm enough to pass through the column. And trying to compress springs, work with small parts... take gloves off and fingers get so cold I couldn't feel anything. Still managed to do it in an hour (book time). Got lotsa "ranch cred" for that job.

Interesting bit of trivia: All 1996 vans that were old body style have tilt column. Non tilt optioned vehicles have no tilt lever.

FWIW it seems like this is a *very* common problem. Aftermarket LED tail/turn that have no brake lights. I've helped a couple of folks and I've diagnosed back to lights both times. One time they installed incandescent lights and everything worked. The other time I didn't hear what the solution was.

What do you guys think of a thread specifically for diagnosing lights with a typical GM brake/turn circuit?

[dsraven]

1project, been there too, working in cold. I spent 4 yrs working in fort McMurray Alberta as a heavy duty mechanic. I remember changing a starter on a dozer about 50 miles north of town out in the bush on a winter road it's a road that's only there in the winter because the ground is a bog if not frozen. Anyway, it was minus 40 celcius, the machine was froze, my tools were froze to the cat tracks and everything you touch is frozen. Work for a few minutes, go warm up in the service truck, go back to work. We had hoses with quick connection to run the warm coolant from the shop truck through the hoses to circulate through machinery's engine to warm up enough to start. My service truck was fully tapped underneath from the front bumper back to the trans, rad nearly completely covered and the big block engine still didn't come up past the bottom side of warm on the temp gauge. Brrrr.

[dsraven]

The led light problem is the reason I suggested to start at the back and see what there is for power there first with the lights unplugged. It's easier than laying under the dash and there is a good chance it's the LED'S causing the problem. If not it is the easy place to start. Test the grounds, the wiring circuits then test the actual lights. Go forward from there. That part only takes a couple minutes anyway.
A new thread for common wiring problems isn't a bad idea. If it could be placed as a highlight instead of buried in with the rest of the threads it would be even better.

[1project2many]

The led light problem is the reason I suggested to start at the back and see what there is for power there first with the lights unplugged. It's easier than laying under the dash and there is a good chance it's the LED'S causing the problem. If not it is the easy place to start. Test the grounds, the wiring circuits then test the actual lights. Go forward from there. That part only takes a couple minutes anyway.

And you're absolutely right about using an incandescent bulb. Typical LED's require less than .1 A. Most resistance issues aren't going to show up with LED.

Add in the "ground through the other filament" issue common on dual filament bulbs and things get really wonky. Trying to tell people the taillight that goes out when you step on the brake is the good one... that's a hard one for folks to accept without proof. Throw in LED's that are polarity specific and everything changes.

No wonder so many people are afraid of electrical work.

[mick53]

Don't let the smoke get out.

[Rickysnickers]

Originally Posted by dsraven

The led light problem is the reason I suggested to start at the back and see what there is for power there first with the lights unplugged......Test the grounds, the wiring circuits then test the actual lights. Go forward from there. That part only takes a couple minutes anyway.

Sorry for sounding dumb, Dennis, but exactly how do you test these things? I have been fighting with my LEDs as well. I have a Power Probe too, but don't really know how to use it.

[/QUOTE]A new thread for common wiring problems isn't a bad idea. If it could be placed as a highlight instead of buried in with the rest of the threads it would be even better.[/QUOTE]

I'm all for that!! We could put it here and/or in the Electrical section. Vette Vette is the moderator there. I'm sure he wouldn't mind, although I would as him first.

[mr48chev]

The only problem that I have seen with LED lights is that you have to have a special flasher or a resistance that matches regular bulbs to get the flasher to flash.

If the OP's turn signals work and the tail lights work. the Led lights aren't the issue. That is called process of elimination.

If the turn lights work ok that means that the wire from the turn switch to the tail lights is good. As long as both work independent of each other.

If the tail lights work and work when the turn lights are flashing that means that tail light wire is good and should mean that the grounds on the lights are good.

If the brake light switch provides power to a test light connected to the wire from the switch when you press the pedal and turns it off when you release the pedal that means that the brake light switch is working.

That leaves the actual problem in the turn switch it's self with something shorting across the board inside the switch or a crossed wire somewhere in the circuit.

By unplugging the turn signal switch plug down on the column and using taking a jumper wire to the proper pins for Brake/turn lights on the chassis side plug from the brake light switch wire he should be able to tell if brake lights come on on each side when he pushes the pedal.

I'm sorry gents but I can blow holes in 3/4 of your ideas you toss out as they have no bearing on the actual problem. Throwing out wild guesses never fix anything they just add to the confusion.