That is different to mine, is it 1957? From what I can see mine appears to have 3 soldered connections and 2 screw connections but it is impossible to have a good look where it is. I was trying to find a change in or out of reverse to be sure the switch will operate the lights but I can't detect any changes with the ohm meter. I'm wondering if it has been wired incorrectly. Getting power there won't be a problem, it is knowing how to wire the switch to make it work. I may have to take it out to inspect it properly.

Ian,
See if this helps.
This is also from the same Electrical Book as before but shows the neutral safety switch.
They may have used two different switches, one without the back up wire connectors but I would doubt it.
Note on the diagram the two wires I have marked. If you have 4 wires off of the neutral safety switch then the two black ones not connected are for the back up lights. The other Blue-Red wires are already connected (or should be if someone has not bypassed it altogether which would be dangerous as it would start in P,R,N or D)
There is not a separate back up light switch as with the Standard and OD. It is all done with the neutral safety switch.
Check the power there in the black wires as before with the ignition on, lights on ad in reverse. If there is no power then the neutral safety switch is bad or the contacts are not aligning with the shifter in the Reverse position.
As Paul stated there "should" be connectors in the 14405 tail light assembly harness already.
Also look at "G" call out in the 1st diagram I posted.
Mine is a 56 with the back up assembly above the tail light but the wiring is the same.


Jim
Norfolk, VA

"MABLE"
1956 Thunderbird Green / Brown Interior (ZE-XG)

"MEAN GREEN"
1956 Mainline (FG-BE)

You won't believe it but I found another soldier terminal hidden in there and I get a connection to the other side testing with the ohm meter when it goes into reverse. There is still no power but it looks like the switch is working for backup lights.
One wire appears to loop back onto the switch and I have the 2 extra screw terminals which is different to the picture you sent. Not sure what is going on there. As I mentioned it is very hard to see anything up there.

Does it start in both N and P?
Perhaps someone was trying to get it to start in P also.
That is a mod that is fairly common.
It is confusing.


Jim
Norfolk, VA

"MABLE"
1956 Thunderbird Green / Brown Interior (ZE-XG)

"MEAN GREEN"
1956 Mainline (FG-BE)

There can be six wires coming out IF that mod has been done.
The plastic insert is taken out of the metal housing and two other contacts are added in the P position to allow it to start there.
The (6) would then be 2 for P start, 2 for Back up lights(R) and 2 for N start.
The new P start wires are then spliced into the existing Blue-Red wires to allow it to start in P.
Do you have connectors in the tail light wiring harness at the end that are not used?
Are there connectors in the harness or are your two extra wires from the R position on the switch connected to the Black-Red wires that go back to the tail lights? That is where the power should be coming from and will light the back up lights when the switch is in R and be passed back to the back up lights.
Tail light and License light wires are "probably" Black with no Red band.


Jim
Norfolk, VA

"MABLE"
1956 Thunderbird Green / Brown Interior (ZE-XG)

"MEAN GREEN"
1956 Mainline (FG-BE)

There are only three wires running into the trunk, no extras for back up lights. Interesting the drawing shows two plugs for backup lights when only one should be needed. From the diagrams you posted and the way it is written I wonder if there is even any wiring coming from the dash area back to the shifter for the backup lights. I guess I will find out what is there when I eventually get around to lifting the carpet.
 My car only starts in neutral but it sounds like those extra two terminals maybe to for starting in park as well. If that was the case there should be two jumper wires but I can only see one from underneath the car. I notice the Tbird suppliers sell a neutral only and at extra cost a park/neutral safety switch.
Thanks for the help. I think it is all starting to make sense now.

Good news.
I've had my seat out and carpet up to see what was there. The two tails shown in the diagram are the two sides of the switch and it is working well. There is no wiring otherwise to power it so a power wire needs to be run from the dash as well. Interestingly when I checked the switch at the plugs I got a 2ohm resistance reading but when I connected up a test light as a load and checked it there was no voltage drop indicated so it all looks good.
I was wondering could anyone tell me what the original backup light wire colour was so that if possible I can keep with the original colours from the factory?

The wires to the back up lights are black with a red tracer all the way back per the Electrical Equipment Installation Manual.  As mentioned before, you should get this manual as it will answer all your questions. Since there are no wires going to the front and to the rear, the car must have come from the factory without back up lights.





54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Thanks Paul.
Yes, the manual is on the list. Unfortunately I didn't think to get one when I was there. The freight kills us to get stuff sent here as it is about $50 minimum or much more depending on the size so I wait until there are enough things to put into a package to make it worth while.

The electrical Manual is listed on pg.27 of the CASCO catalog.
While you are browsing the pdf of the catalog take a look at pgs.49-51. There are a couple of diagrams that list the Harnesses. One is the 14405C that Paul mentioned earlier.
Also listed are rear lenses with the white lens for the backup light itself if you have not sourced them locally.
Review that page I posted earlier as that is from the Electrical Manual. Wiring Color Codes are on the lower left.
There may be enough there to get you above your $50 breakpoint.
An email to them may help clarify just what harnesses you need.

Jim
Norfolk, VA

"MABLE"
1956 Thunderbird Green / Brown Interior (ZE-XG)

"MEAN GREEN"
1956 Mainline (FG-BE)