neutral safety switch/backup lamp question.

[222lifer]

Hi everyone, new member/owner here with a question that may have been answered already.

I recently purchased a 73 Duster that spent the most recent part of her life as a trailer queen. This is an original 340 Duster with a 727 transmission. It has a B&M mega shifter changing the gears.

I noticed that the backup lamps weren't working and upon further inspection, there is no wiring going to the neutral safety switch on the transmission. The 3 prong switch is in place on the tranny.

I am not sure what I need for this project so I ordered a few things that came to mind. I have a micro switch for the shifter if I need that and the 3 prong female harness for the neutral safety switch. I don't have a clue as to wiring this thing up.

Thanks in advance and any help or suggestions would be greatly appreciated.

 

[67Dart273]

I would not use the shifter mounted switch. The original trans switches are very reliable, and eliminate the possibility that a misadjusted shifter will start in gear.

You should have a start relay with two "push on" quick connect terminals. Either of these goes to the start wire from the key, and the remaining one goes down the firewall, and to the CENTER pin of the neutral switch.

The two outer pins of the neutral switch are your reverse lights.

You have a shop manual? There was major wiring changes between 72--74, and I'm not sure whether 73 fits one or the other.

 

[70aarcuda]

as said ...you the neutral safety switch in transmission...

center wire goes to the starter relay switch G terminal which is ground....

a wire going to the neutral safety switch on the shifter is probably already on that terminal.....

you can buy the correct wiring harness from Evans wiring..as the back up lights will plug into one of the wiring harnesses that goes into the bulk head.

http://www.evanswiring.com/catalog.htm

 

[222lifer]

Thanks guys for the help. I am at a loss as there is "0" wiring down there. Nothing on the shifter but the light for the gear selector. No harness and no wiring for the neutral safety switch on the tranny. I may just pop for a painless wiring kit and rewire the entire car.

 

[67Dart273]

Painless or not you still need the 3 prong harness connector/ pigtail that fits the trans. These were the same for "about a thousand years" after 69

 

[RedFish]

At the starter relay... it should have a yellow wire that gets power from the ignition switch in the start position. Another terminal should have a brown wire going to the NSS ( neutral safety switch ). Assuming th car starts today, that brown wire would be attached directly to ground.
The 2 wires for the back up light circuit could be a little more difficult to find, just depends on where they were chopped. Anyway... At the bulkhead connector on the firewall, the connector at far right has wiper motor wires mostly, another pair went through there and dropped straight down the firewall toward the trans. Wiring diagrams would help but I think those were a purple and either a white or a purple with white tracer.
If they aren't found there under the hood, you'll need to go to the under dash side and hunt them.
I would get these 2 wires started out the firewall first and bring the brown NSS wire from starter relay along the left inner fender and across to join those other 2 creating a 3 wire harness goint to the trans switch. That's how the factory did it, until 74 model anyway.
Hope this helps

 

[Pompis]

Here is the 3 prong harness connector 67Dart273 talking about.

http://www.ebay.com/sch/i.html?_trk...neutral+safety+switch+s747&_sacat=0&_from=R40

Buy one of those and connect it on the transmisssion. There is a combination reverse light/neutral safety switch on the transmission case. Two wires are for the reverse lights (feed power in one side and the feed out the other, doesn't matter which way), and one is a ground for the neutral safety switch. Use your multimeter and whichever one is ground with the trans in park is the neutral safety switch wire.

 

[222lifer]

Painless or not you still need the 3 prong harness connector/ pigtail that fits the trans. These were the same for "about a thousand years" after 69

I have the pigtail. My local Car Quest store had that piece to the puzzle. Thanks for the help.

 

[222lifer]

I would not use the shifter mounted switch. The original trans switches are very reliable, and eliminate the possibility that a misadjusted shifter will start in gear.

You should have a start relay with two "push on" quick connect terminals. Either of these goes to the start wire from the key, and the remaining one goes down the firewall, and to the CENTER pin of the neutral switch.

The two outer pins of the neutral switch are your reverse lights.

You have a shop manual? There was major wiring changes between 72--74, and I'm not sure whether 73 fits one or the other.

Need to get a shop manual. This duster is new to me. Thanks for the info.

 

[222lifer]

At the starter relay... it should have a yellow wire that gets power from the ignition switch in the start position. Another terminal should have a brown wire going to the NSS ( neutral safety switch ). Assuming th car starts today, that brown wire would be attached directly to ground.
The 2 wires for the back up light circuit could be a little more difficult to find, just depends on where they were chopped. Anyway... At the bulkhead connector on the firewall, the connector at far right has wiper motor wires mostly, another pair went through there and dropped straight down the firewall toward the trans. Wiring diagrams would help but I think those were a purple and either a white or a purple with white tracer.
If they aren't found there under the hood, you'll need to go to the under dash side and hunt them.
I would get these 2 wires started out the firewall first and bring the brown NSS wire from starter relay along the left inner fender and across to join those other 2 creating a 3 wire harness goint to the trans switch. That's how the factory did it, until 74 model anyway.
Hope this helps

Thank you for the reply. This will be a big help.