Front turn signal problem on 1956 Thunderbird

You know, on older harness where the colors have faded or dirty, wiping the wire(s) with a little DAWN (gingerly) might make the colors and trace colors more identifiable.

There was a white lanoline hand cleaner used in the olden days and I can't remember the name (GoJo? - CRS).
 
Yes, to a degree. If you will notice there are two types of barrels in the connector/junction block. Some are singles and some are doubles. The singles are for things like the signal lights as there are separate lines for each side in and out.. The doubles may have a single wire going in, with two wires going out, like for the parking lights which have one input and two outputs.. So you have to be careful when installing the wires.


 
zuburg said:
. . . Does each specific wire need to be in a particular position on the junction block or just as long as the input and output wires are lined up in the same position, it works. I’m trying to figure which wire is what. It was no problem when I could see one end of the wire and trace it to the other end like the wires from the horn relay to the horns. It’s the random wires coming out of the old harness and colors are hard to discern.
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In a particular position? Technically no, as long the wires for each function line up, especially the L and R turn signal connections. But the more jumbled up they are the harder you make it on yourself.
After an engine compartment repaint I wanted an easy to follow pattern for later trouble shooting. Sorry it's a long story but the background info helps me with the explanation. (CRS)

I added yellow labels to the first three photos below, they're not found on a Ford diagram.
The 4th photo below is a Ford diagram, these usual symbols in published wiring manuals don't look like the real junction blocks at all, don't show you where in the actual block to place the bullet connectors and only gave me a headache. Wire colors in the diagram could be helpful but not if you can't see them in the car.

Like your '56 my '55 also has indistinguishable colors on most of the front lighting wires.
I wanted an easily visualized pattern using the actual junction block that could be quickly confirmed under the hood while bleary eyed at midnight.

You'll need a 12v test light and a jumper wire from a 12v power source. I used the battery in the car.
Connect the test light one at a time to the lighting power wires coming from the dash and operate the light switches until your test light comes on. Attach a piece of masking tape to each wire noting the function of that specific wire. Hi & Lo headlights, left & right turn, parking.
The ground wire from the dash should have a ring lug on it instead of a bullet connector.

Using the 12v powered jumper wire connect it one at a time to wires going out to the front light fixtures. When each lights up attach a masking tape label description to that wire. Troubleshoot and repair problems as needed.

Knowing the color (or indistinguishable color) of each wire is no longer necessary because all the wires are labeled with their function.

Having the turn signal connectors on the right side of the upper layer (as original) started me on a pattern. With the high beam headlight connections also in the upper layer the brighter functions were now all in the 'higher' layer.
Left & right being side by side for each light fixture in the same L & R orientation as on the car.

With the 'lower' brightness dash power wires in the lower layer the L & R low beam connections could be just below the L & R hi beam connections, and the L & R parking light connections are just below the L & R turn signal connectors.
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paul2748 said:
HUH ?? Pins on the socket ????
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This message is hidden because paul2748 is on your ignore list.​

In the ever-evolving automotive industry, automotive pin terminals play a vital role in ensuring reliable electrical connections.

What Is an Automotive Pin Terminal?​

An automotive pin terminal is a type of metal connector used to join electrical wires within a vehicle’s wiring harness. Typically made of copper alloys or brass, pin terminals are inserted into housings or connectors and ensure stable, low-resistance contact. These terminals are widely used in applications ranging from engine control units and infotainment systems to lighting, battery packs, and sensors.
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SOURCE - https://www.gvei.com/the-role-of-an-automotive-pin-terminal-in-vehicle-electrical-systems/

You really need to stay current ...
 
I would advise not deviating from the OEM WIRING, unless one is making modifications such as integrating EFI into a system, etc.

To chase an electrical fault is a SERVICE REPAIR.

To chase (or pay someone to chase) a modified wiring harness can be both frustrating and expensive (outside repairs).
 
I’m focusing first on the front left double stack junction block since everything worked before an experienced mechanic with much experience with early birds replaced the front wiring harness. I can see the wires in this harness exit the block and go across to the front right block. What I don’t know is what may have been done over the last 70 years. Many of the wires look pretty old and stiff (like me). The colors from the main harness are hard to determine but. I tried to capture shatter I could. I created a chart what is supposed to represent the double stack block looking down on the top with what I think should be input wires from the main harness going into the block from the left and wires that exit the block on the right. The first column is supposed to be the factory functions for each terminal (I numbered each terminal 1-4 on the top row and 5-8 on the bottom row). If you were looking straight on to the front of the blocked the terminals would be:
1 2 3 4 top row
5 6 7 8 bottom row

I tried to check for power on each wire going into the block and noted which had power. I then noted what was working on the right of the block followed by a description of the wire exiting the block.

I thought a few things looked strange. This was all to try to find why neither front turn signals work. Both rear turn signals work correctly although both das indicators flash for both left and right. So I believe the flasher is working. I understand that most of the terminals are straight thru connections but a few adjacent are internally connected so you could have one power wire going into but two wires going out to both head lamps for example but I don’t see how mine are doing that (even though both head lamps work both normal and high beams.

I’m attaching both a photo and PDF file of the chart I made. Would appreciate any ideas on why the front turn signals don’t work. I wonder if there is one or 2 wires completely missing?

It’s a lot to ask, but I thought I would throw an Hail Mary.

Thanks
 

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DMSFRR - Your post was great. I missed it as I did some others that went to page 2. I wish I saw this before I traced the wires and posted my map. I'll try testing again and replugging as needed. I guess plugging the back end going to the lights will be some more trial and error. Another problem I have is most of the wires are very short and stiff so hard to get to, but I'll get it done.
 
zuburg said:
... everything worked before an experienced mechanic with much experience with early birds replaced the front wiring harness.

I can see the wires in this harness exit the block and go across to the front right block.

What I don’t know is what may have been done over the last 70 years.

Many of the wires look pretty old and stiff (like me). The colors from the main harness are hard to determine ...
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There is your answer, it has been hacked.

CLICK HERE - https://www.caretxdigital.com/
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And I am going to tell you one other thing.

Not so long ago, bulbs were coming in from CHINA (box store specials). The two contacts (or pins) on the bulb base were not made long enough to fully contact the lamp base contacts.

The base was bright whereas the US were brass.
 
I think I may have found my problem. I think what I thought was the input side (be cause it was closest and pointing to the old harness) is actually the output side. My mechanic put his 4 wires that crossover to the right side into the back of the block facing the front of the car near the hole to route the wires over to the right side, so no wonder I was confused. 3 of the 4 functions work on the right side with only the turn signal not working.

Now that I look again, all 8 terminals on what I thought was input are filled which makes me think it is the output side. On my count only 5 power wires are required going into the block.

Now this brings me to a question that bothered me. There was one wire coming out of the main harness plugged into what I thought was the output side, opposite the top right terminal of the 8 terminal block. This wire did not have power for any of the 5 functions. If it is true that this wire was going into the input side, with no power, what would it be for? Sending a signal back to the dash?

I may have to flip the block around because I don’t think the wires coming out of the harness will reach the other side.

I’ll let you know how it goes.
 
My bulbs worked fine for 7+ years until recently after a mechanic replaced the front wiring harness.
 
UPDATE! I got all the wiring sorted and all lights and turn signals are working. Thanks again to DMSFRR, his pictures of the actual double stack block with his annotations on how to place the wires is what helped the most. I ended up removing all the wires and connecting them in the logical order in the pictures.

Now I just have to splice one of the 3 wires that go to the alternator that the mechanic included in the new harness that crosses over to the right side. One of his splices pulled loose with just moving it out of the way.

Thanks to all who put up with all my long-winded uneducated questions. I used ChatGpt for some of my research and it gave amazing detailed answers, but based on the little knowledge I had and info from the Forum, I had to keep questioning it and pushing back with the knowledge I had. It kept apologizing and correcting itself over and over. At the end I told it I don’t know if it told me or I told it how it worked.
 
zuburg said:
UPDATE!

Thanks to all who put up with all my long-winded uneducated questions. I used ChatGpt for some of my research and it gave amazing detailed answers, but based on the little knowledge I had and info from the Forum, I had to keep questioning it and pushing back with the knowledge I had.
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THANX! you for bringing the problem(s) here for discussion. We all learn.

You didn't mention it had an ALT upgrade, That is where most of it began (that and old wiring) most likely.

Once you cut into a wire harness, the fun begins.
 
There wasn’t an alternator change. It’s just my mechanic included the 3 alternator wires in the new wiring harness that included the 4 wires from the double stack block crossing over to the right side. I re-spliced the one alternator wire that had pulled out this morning. I think everything is all buttoned up now.
 
zuburg said:
UPDATE! I got all the wiring sorted and all lights and turn signals are working. Thanks again to DMSFRR, his pictures of the actual double stack block with his annotations on how to place the wires is what helped the most. I ended up removing all the wires and connecting them in the logical order in the pictures. ...
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You're welcome. I'm glad it's working for you.
Like other ideas it came to me in the middle of the night after completely giving up on it the evening before. :o
 
Don't know when Ford changed things, but in 54 cars turn signals and stop lights were connected through turn signal switch.
 
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