Back up lights on 56 Crown Vic

[Woodie UK]

Just noticed the back up lights on my 56 Crown Vic are not working...they may not been working when I first bought the car 12 months ago..never looked until now, Doh!

There doesn't seem to be any power at the switch and I can't find any wiring diagram in the handbook or shop manual. Has anybody ever located an appropriate wiring diagram? Can't find any trace of any fuses!!!

Also, I can't find a replacement sw (in case I need on) listed in any of the normal suppliers catalogs. Anybody got any ideas?
Colin

[miker98038]

Larry’s shows the switch for the manual trans, possibly the auto uses the neutral safety switch. I’m a west coast guy so I use Larry’s but there got to be someone closer to you.

Here’s the link to the pass car catalog.

https://www.larrystbird.com/wp-conte...-passenger.pdf

[fordrodsteven]

I would think that a back up light switch would be common to most all Ford products of the era. Possibly try looking at a Thunderbird switch in one of those supplier catalogs to see if it looks like what you want.

[fordrodsteven]

Mac's Auto parts lists a switch for standard shift transmission and it lists a different switch for automatic transmission.

[5851a]

Not sure on Crown years but I seem to remember something about reverse light power coming through park lamp or headlamp, so they only work when lights are on. May be on earlier cars, or I'm thinking of another make.

[fordrodsteven]

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Originally Posted by 5851a

Not sure on Crown years but I seem to remember something about reverse light power coming through park lamp or headlamp, so they only work when lights are on. May be on earlier cars, or I'm thinking of another make.

I think this is true for all the fords of those years. The thinking was you don't really need the lights to go on unless it was dark enough to have your headlights on. The designers of the time didn't think in terms of letting other people know you were backing up. Their thought was you will need to be able to see when it's dark.

[fordrodsteven]

Also, I just looked at one of the Thunderbird web sites and it shows the (automatic transmission) neutral safety start switch has two wires coming out of it that turn on the back up lights.

[fordrodsteven]

I pulled this from one of the Thunderbird sites:
well, i don't know exactly on a manual tranny, but on a an automatic, it is located with the floor shift assembly--you can get to it under the car, drivers side....it also incorporates the back-up lights switch - so you have 4 wires going to it--the two blue wires are the neutral start function--there is no start in 'PARK'---just neutral - but you can now buy one (for $10 more than a stock replacement) that has been modified internally to start in park or neutral..all the big t-bird venders have them in stock---($110.00 and $120.00)....make sure you have voltage to the switch with the key on....and you have not melted any wires cause they are close to the exhaust pipes.....two white wires are for the back-up lamps AND the switch is ADJUSTABLE---make sure it has not fallen out of adjustment......ed mlynek

[KULTULZ]

See If This Works- https://norwalkkiwanis.org/images/19...agrams-classic

AT or ST?

[Herman Munster]

The neutral safety switch, b7az-7a247-a, that is for 55-57 cars is also listed as a backup light switch.

[paul2748]

Turn the parking lights or the headlights on and then put it into reverse. The backup lights work through the headlight switch and the switch needs to be pulled out.

[Grumpy Rick]

Recently installed a new neutral safety switch on my '55 T-BIRD (Fordomatic). Found it had no factory wiring for back up lights, apparently it was an option. You might check yours.

The lights were installed on the car at some point, but never hooked up. No factory wires in the trunk either. Rewired to make it work.

BTW, I used the modified switch to start in park. Works good.

[Woodie UK]

Some great answers and responses...thanks guys
Checked the backup lights with the parking/headlights on, ign on, car in R (it's an auto)..but still nothing.

There doesn't seem to be any power going in or out of the Neutral Safety sw so going to get a new one +new wires and hope that works.
Thanks again
Colin

[Herman Munster]

Sounds like you need to get a wiring diagram before you start tossing parts. You then should check the switch for continuity in the Reverse selection with a multi-meter.

[rotorwrench]

Ford was poor about putting good wiring diagrams in their overhaul and shop manuals. What makes it worse is the accessory option factor. The wiring instructions came in the kit and may have not been included in any original wiring diagrams. The diagrams I found for 1956 on line don't show them on the main diagram.

It would be simple enough though. The power may come off the light switch or directly off the main buss circuit breaker then on to the reverse light switch. A single wire likely feeds back with the harness to the trunk where it would split for the two reverse lights. Some diagrams available have the accessory diagrams separate but some don't have them at all

[Herman Munster]

I was thinking about the electrical assembly manual that was released for 1956.

[Alaska Jim]

If you have no power going into the switch like you said, most likely you have a wiring or fuse problem, this needs to be checked out before you spend your money on a switch, and find out it still does not work because you have no power to it. Start at the back of the car and find the wires to the back up lights, to verify that it does have the wiring installed, then following the wires, checking to make sure they are not cut, corroded, Burt in two, up to the reverse/back up light switch. I have not had a '56 ford since I was 18, so I am not sure about the fuse situation. seem that there should be some type of fuse, but maybe not. You said you have no power in or out of the switch. if you are checking it at the switch, and you have no power, I would think that the neutral safety switch would also not be working correctly. I may be wrong about this though, as I said It has been a long time since I have owned one. I am sure these other fellows will correct me if I am wrong.

[miker98038]

I’m just thinking out loud here, cause I don’t have the wiring diagram. The neutral safety sw is a pass thru, power from the start position to the solenoid. The back up light sw needs power from somewhere, and when the shift linkage engages it in reverse turns on the back lights. As suggested above, it might very well come from the headlight switch and only work when they’re on. One of the problems with our old fords is almost everything was inline fuses, no fuse panel. In some cases there’s a circuit breaker under the dash, at least on my ‘bird. So checking the sw with a multi meter for continuity and voltage will be a start. Looking for broken or shorted wires as Jim suggest next. Some will have to be done with the power on/off, or the bulbs out. Patience, you’ll find it.

[dmsfrr]

Originally Posted by miker98038

I’m just thinking out loud here, cause I don’t have the wiring diagram. The neutral safety sw is a pass thru, power from the start position to the solenoid. The back up light sw needs power from somewhere, and when the shift linkage engages it in reverse turns on the back lights. .....

Yes, power for the backup lights and the neutral safety switch comes from two different sources.
The inside of the switch is actually two separate switches in the same housing.

The NSS contacts on the switch get power from the "S" / Start position of the Ign key switch.
From the nss that circuit (red/blue wire) continues up to the "S" terminal on the starter solenoid.

http://www.oldcarmanualproject.com/t...re5765-195.jpg

The backup-light half of the switch gets power from the Headlight or Ign switch. From the backup-light switch a wire goes to the lights at the rear of the car.

The comment from rotorwrench about the wiring installation instructions being in the optional kit could well be true. I had looked thru a few manuals to confirm the power source of the missing / optional backup light wiring in my '55 and haven't found anything yet. I'll be connecting it to the Acc terminal of the Ign switch, personal preference.

Originally Posted by fordrodsteven

I would think that a back up light switch would be common to most all Ford products of the era. Possibly try looking at a Thunderbird switch in one of those supplier catalogs...
...just looked at one of the Thunderbird web sites and it shows the (automatic transmission) neutral safety start switch has two wires coming out of it that turn on the back up lights.

'55/'57 T-Bird's with an automatic use a different style switch than the 'full-sized' cars, one that's bolted into the floor shifter.
photos below
.

[Daves55Sedan]

Assuming the car was factory equipped with a Ford-O-Matic, there is a factory installed "Starter-neutral safety" switch installed at the base of the steering column near the back of the steering gearbox. There is a short accessory harness with two red/black wires that connects to inline bullet connectors from the main harness under the hood and the other end connect to the switch with bullet connectors. The other two terminals on the switch are "push-on" style terminals and they are for the back-up lights. Fomoco provided a second accessory harness with two wires that attached to those two terminals. That harness runs thru the firewall grommet under the dash, one wire connecting to the power source and the second wire connecting to the wire that goes to the trunk of the car for the back-up lights.
These switches need to be adjusted perfectly or the contacts in the switch will burn up very quickly (particularly the start circuit). The reproduction switches are available from Mac's and Concours Parts but they are upwards of $45.00 now and they are foreign made pieces of junk that will not last long even if adjusted perfectly.
It may not be factory correct, but I have my backup lights wired from the accessory terminal of the ignition switch rather than the headlight switch, so that the backup lights come on day or night if the gear selector is in reverse, but the lights will not illuminate if the car engine is not running.