Flawed Success Turn Signal Puzzle

[Tire Guy]

Today I worked on restoring all the lights at the back of the truck. I had no brake, tail or turn signals. The PO had installed a new wiring harness but nothing worked right. So I installed:
LED tail lights
LED turn signals in bed rail pockets
LED license plate lights
LED bulbs in front for turn signals
LED flasher

I pulled everything down and started from scratch and ran new power wire for the brake lights. I test ran everything to make sure all the lights worked then did the install and wired everything up and they look great. I soldered and shrink wrapped all connections and did a nice tuck on all wires. The brake and tail lights work like a modern car.

However, the turn signals all flash front, back, left and right with the turn signal lever in either position. Like emergency flashers. The turn signal lights also come on with the tail lights and they shouldn't. They look great but not how they are supposed to work.

Everything is wired correctly from the firewall back. Any ideas on what could cause this? I am stumped.

[1project2many]

Check the front lights to ensure turn and park aren't inadvertently connected and make sure the front lights are both properly grounded. Check turn signal switch (what switch are you using again?) to ensure it's not actually supplying voltage on opposite side when signaling. Did you opt for LED's with resistors so the turn flasher rate stayed correct? If so, then bad grounds at the rear lights could be a problem. Is your brake light switch wired to the turn signal properly? Is the turn switch wired properly?

For diagnosis methods, the key is to isolate where / why power is bridging the circuits. You could disconnect one light, test for change, reconnect. You could try temporarily installing jumper wires to a good ground point. A simple test would be to disconnect wires near the firewall and supply 12V to the LH and RH stop wires for the rear lights, one at a time. If the lights work fine you can move to the front lights. If all lights are fine then you've got diagnosis to do inside the cab.

Good luck.

[57chevyman]

i had a similar issue where everything was connected correctly, but both blinkers would blink instead of just the side that was supposed to blink. i ran a wire from the back of one of the tail lights and grounded it to one of the bumper bracket bolts. that fixed my problem the ground thru the tailight bracket sometimes isnt strong enough.
not sure if this applies to you with LED lights.

i took a 3 ft section of wire, stripped both ends, connected one end to the back of the tail light. while the blinker is on, touch the other end to a good ground. i was able to just touch the edge of my bumper, and like magic, the blinker started working correct. with your painted bumper, youll have to try grounding it somewhere else. if you find the ground wire fixes the problem, then you can proceed with neatly running the wire and hiding it, bolting it to the frame
good luck!

[_Ogre]

ran new power wire for the brake lights

from where? to where? what harness? what column?
the more you tell us the better we can trouble shoot

with a new harness, your turn signals are your brake lights
you have three 12v+ power into the turn signal switch, flasher, hazard and brake switch
then a wire out to each corner of the truck
the other wire to each corner will come from the headlight switch for running lights

[Tire Guy]

Originally Posted by _Ogre

from where? to where? what harness? what column?
the more you tell us the better we can trouble shoot

with a new harness, your turn signals are your brake lights
you have three 12v+ power into the turn signal switch, flasher, hazard and brake switch
then a wire out to each corner of the truck
the other wire to each corner will come from the headlight switch for running lights

I had to run a wire from the brake light switch and bypassed the turn signal wires. They are dedicated to the turn signals only. They are yellow and green like your chart.
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[mr48chev]

I think 1project2many nailed it in his first paragraph. Since the stop and tail lights seem to work correctly and the problem is in the turn lights it is entirely possible that you either have reversed the wires on one of the front park/turn lights so that when you hit the turn switch you are actually turning on all four lights as turn lights as well as as the rear turn light on the side you have the switch turned to.

It's also possible that one of the front lights isn't grounded and is grounding back through the whole park light circuit turning on the lights.

[Tire Guy]

The turn signal switch is OE.

Update:
Grounds are all good ft and back.

New symptom:
When the turn signal lever is set one way the off side still flashes but not as bright.
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[Tire Guy]

Update#2:
I checked the wires coming out of the turn signal switch. The are labeled LF LR and RR
RF. And all of them have power when the switch us on left or right.

This indicates to me the problem is with the switch. Right?

And as Ogre has taught me. Here are some pictures.

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[1project2many]

Hmmm... That is not an OE switch from 1957. That is a later column. That style column started use around 64 and was used through the '70s in trucks and vans. And it makes this problem a bit easier to understand imo because the original 55-59 bucket had no hazard light switch. This one does. So it is possible to have either a faulty hazard switch, or the hazard switch is turned on and the switch is wired improperly. There is a great thread on 67-72chevytrucks.com with proper wiring including colors. Find it here. The V8 engine and cab diagram is what you want. Follow the link to the full size version. It's too big to post as an image. You may also find the diagram at the bottom of this post helpful.


The half moon connector on the right of the truck diagram is the original connector on your column. It's also represented on the image below. It looks like it's missing in your truck now. But it appears that the original wiring is still there. I only see four wires connected in your picture which would be a problem as the turn signal circuit should have six wires to work properly and seven if you have a hazard flasher.

The chart that Ogre posted is typical of GM for cars made into the '90s. The turn signal flasher is powered with the key on. White comes from the brake light switch. It has power when the brakes are applied. Light blue is the LH (driver's) front turn. Dark blue is the RH front turn. Yellow should be the LH rear turn, and green should be the RH rear turn. The brown wire connects to the hazard flasher. It could be considered optional. If there's a black wire it should connect to the horn relay.

The truck wiring would have been the same originally with the exception of the hazard wiring. I don't know if your harness colors are the same but I see white to purple, something that looks like a melted butt connector that may have two wires connected, and nothing resembling the rear turn/stop light coloring. You should correct the wiring at the column. Remove the new brake switch wiring as it's likely the cross between right and left side signals. What happens internally when selecting a turn is the switch disconnects the brake light from the brake switch and connects it to the turn signal flasher. Without that switch you need diodes or you need an additional bulb.

[mr48chev]

I'm thinking that is a mid 60's GM car column. I looked at my 71 truck and it that bottom shield doesn't go all the way to the dash on it.

Clean the red paint off the wires so you can see the color of the wires and go by the color codes for a 67/68 Chevelle or other 66/68 GM car. You have to match the color code of the wire from the switch to the color code of the wiring kit which should match GM anyhow.

I hate to say anything negative about the quality of anyone's handywork but 90% of your problems may be right the in that soldered together mess that you will end up cutting apart if the switch is bad. If it was brought to me with the wiring issue the first thing I would do is cut that out and put round male/female connectors in it so the switch could be removed or the wires could be switched if they were wrong.

I've spent a half hour hunting and can't find a color coded wiring diagram just for the switch but one should be out there.

[mr48chev]

This should read off the correct color codes for the wires out of the switch.


I'm sure that that switch is early enough so that it is setup with the stop/turn lights on the same bulb and not one that has a separate stop light bulb like the real late models do.

[Tire Guy]

Well this certainly proves I don't know what I'm looking at...

The truck has a 1969 Chevy Nova sub-frame and a 350 motor from a 1976 truck/van. Future projects include replacing the steering column and that rat ass steering wheel. But all things in their time.

Looking at the mess in the photo you can imagine the mess the PO made of the wiring at the back and can understand why I cut it all out and rewired everything from the firewall back. Now it is my mess.

I will rent a steering wheel puller and investigate the switch. My guess it is worn out. Then I can clean up the wire mess with a new switch install. Luckily the wires are all plainly labeled.

If anyone can positively identify the steering column and switch that will help.

I will update as I go along. Thanks for the advice guys. It is much appreciated.

[1project2many]

I'm thinking that is a mid 60's GM car column. I looked at my 71 truck and it that bottom shield doesn't go all the way to the dash on it.

Interesting. I don't think I've ever had a chance to compare them side by side before.

If anyone can positively identify the steering column and switch that will help.

This page might help once you have access to the switch.
https://www.yearone.com/Catalog/1964...-.-turn-signal

[mr48chev]

I went out and looked at the column in my 71 and it is different in that the tube of the column is exposed below the shift collar. I cheated and searched out a 67 Chevelle column and photos came up with the cover over the bottom of the column like his has. 66,67 & 68 looks quite similar, should have the 4 way and no key in the column that began in 69 with most GM cars. That's actually a clean looking no clutter column that looks quite proper in there.

[57chevyman]

Before you take the steering wheel off ... Did you have working front blinkers that now don't work after you added tail lights to the mix? That's what happened with me ..
I think your problem is in the wiring. I'd certainly rule out the wiring before pulling the steering wheel off
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[Tire Guy]

[QUOTE=57chevyman;7255104]Before you take the steering wheel off ... Did you have working front blinkers that now don't work after you added tail lights to the mix? That's what happened with me ..
I think your problem is in the wiring. I'd certainly rule out the wiring before pulling the steering wheel off
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The LF was working well and the RF was very dim. Either way the switch has to be replaced. It is worn out, I can't find neutral(off) on it any more. It is the most obvious and if not the answer I'll move to the next most likely.

The wiring on this truck will be an ongoing problem. I am good at hanging parts but electrical gets my blood pressure up....

[mr48chev]

Tie a length of wire or string to one of the wires in the switch harness when you pull the old switch and pull it up through the column. Then you can tie that to the plug/connector on the end of the new switch harness and pull it back down though the column without a big fight. The parts houses also sell new pigtails to connect the wires in the truck to the switch plug rather than cutting off the plug and doing it as it is now.

I'd pull the switch out and then match it to the replacement. NAPA stores have or can get complete turn signal switches. Check on this one as I think it will be pretty close to the right one. http://www.napaonline.com/Catalog/Ca...187_0306391954


Note: a search shows that you can get the switch for a lot less online if it is the correct one.
http://www.rockauto.com/catalog/rafr...rttype=4832&ck[ID]=0&ck[idlist]=0&ck[viewcurrency]=USD&ck[PHP_SESSION_ID]=s3ooc7isquimgu53u9iquqdke5

[Tire Guy]

Originally Posted by mr48chev

Tie a length of wire or string to one of the wires in the switch harness when you pull the old switch and pull it up through the column. Then you can tie that to the plug/connector on the end of the new switch harness and pull it back down though the column without a big fight. The parts houses also sell new pigtails to connect the wires in the truck to the switch plug rather than cutting off the plug and doing it as it is now.

I'd pull the switch out and then match it to the replacement. NAPA stores have or can get complete turn signal switches. Check on this one as I think it will be pretty close to the right one. http://www.napaonline.com/Catalog/Ca...187_0306391954


Note: a search shows that you can get the switch for a lot less online if it is the correct one.
http://www.rockauto.com/catalog/rafr...rttype=4832&ck[ID]=0&ck[idlist]=0&ck[viewcurrency]=USD&ck[PHP_SESSION_ID]=s3ooc7isquimgu53u9iquqdke5

Thanks. The key will be finding the right one.
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[Tire Guy]

Update:

I pulled the switch and it is a mess. It matches over to a 67-72 Chevy truck. Oreilly's has the part for $50. I'm still checking alternate sources.

I don't see any way to get the plastic connector back down through the steering column. I ran a wire through it when I pulled the old one out but the opening in the steering collar is very small.

[solidaxel]

Originally Posted by Tire Guy

Update:

I pulled the switch and it is a mess. It matches over to a 67-72 Chevy truck. Oreilly's has the part for $50. I'm still checking alternate sources.

I don't see any way to get the plastic connector back down through the steering column. I ran a wire through it when I pulled the old one out but the opening in the steering collar is very small.

You do know you can "un pin" the wires from the plastic connector and it may make it easier to fish back in

[Tire Guy]

Originally Posted by solidaxel

You do know you can "un pin" the wires from the plastic connector and it may make it easier to fish back in

Looking at how tight this I won't have any choice. Thanks for letting me know, I want a clean install.
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[1project2many]

You could remove the terminals from the connector. Edit: Solidaxel posted the same thing while I was looking for a picture! There will be little locking tabs inside the connector that can be bent with a small, flat tool or (sometimes) a paperclip. Mark each position with a letter or number to help ensure they are reinstalled correctly. This is one version of a terminal removal tool that is very handy to have.

[Tire Guy]

Originally Posted by solidaxel

You do know you can "un pin" the wires from the plastic connector and it may make it easier to fish back in

Can you give me a better description on how to remove the wires from the connector? I'm scared I'm going to break this $50 part. I don't see anything to bend. It has plastic ridges on both sides that keep the pin in place.

[OrrieG]

I made a tool to reuse my connectors, wasn't ambitious to try and find one to buy, NAPA has the brass connector pieces.

[Tire Guy]

Originally Posted by 1project2many

You could remove the terminals from the connector. Edit: Solidaxel posted the same thing while I was looking for a picture! There will be little locking tabs inside the connector that can be bent with a small, flat tool or (sometimes) a paperclip. Mark each position with a letter or number to help ensure they are reinstalled correctly. This is one version of a terminal removal tool that is very handy to have.

Would it be the fork for the ALDL connector?