Reverse light issue on a 76
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Reverse light issue on a 76
Hello all!
I've been working on getting a 76 F-150 SWB/4x4/C6/360 running and I'm down to electrical. All the lights work as designed including marker, brake, turn signal, hazard, headlights and high beams EXCEPT my reverse lights. The come on intermittently and it's really making me crazy. I've pulled my neutral safety switch and cleaned the contacts, realigned it and traced the wires and they all look solid. The neutral safety switch is working as I can't start the truck in any gear but Park and Neutral. I've inspected the wire harness from front to back and pulled all ground connections and made sure they all had bare metal contact.
My question is, does the neutral safety switch work the reverse lights on this truck or am I chasing a gremlin? IF the neutral safety switch doesn't activate the reverse lights, where do I need to look next?
Any help will be much appreciated!
I've been working on getting a 76 F-150 SWB/4x4/C6/360 running and I'm down to electrical. All the lights work as designed including marker, brake, turn signal, hazard, headlights and high beams EXCEPT my reverse lights. The come on intermittently and it's really making me crazy. I've pulled my neutral safety switch and cleaned the contacts, realigned it and traced the wires and they all look solid. The neutral safety switch is working as I can't start the truck in any gear but Park and Neutral. I've inspected the wire harness from front to back and pulled all ground connections and made sure they all had bare metal contact.
My question is, does the neutral safety switch work the reverse lights on this truck or am I chasing a gremlin? IF the neutral safety switch doesn't activate the reverse lights, where do I need to look next?
Any help will be much appreciated!
Hotshot
Joined: Apr 2009
Posts: 14,333
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From: Stanley, VA
It does sound like an alignment problem with the NSS.
There's a particular procedure to adjust it. I'll look it up and update this post.
Hotshot
Joined: Apr 2009
Posts: 14,333
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From: Stanley, VA
NSS switch adjustment
1. loosen the two switch attaching screws.
2.Hold the selector lever against the neutral stop.
3.Move the sliding block on the neutral switch to the neutral position. Working from the rear side of the switch, insert a 0.091" diameter gauge pin (#43 drill bit) in the gauge pin hole.
4. Slide the switch as needed to permit the switch actuating lever on the steering column to contact the switch sliding block.
5. Tighten the two attaching screws and remove gauge pin.
6. Check the operation of the switch.
1. loosen the two switch attaching screws.
2.Hold the selector lever against the neutral stop.
3.Move the sliding block on the neutral switch to the neutral position. Working from the rear side of the switch, insert a 0.091" diameter gauge pin (#43 drill bit) in the gauge pin hole.
4. Slide the switch as needed to permit the switch actuating lever on the steering column to contact the switch sliding block.
5. Tighten the two attaching screws and remove gauge pin.
6. Check the operation of the switch.
Hotshot
Joined: Apr 2009
Posts: 14,333
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From: Stanley, VA
The contacts can be corroded or they could also be weak and not making good contact with the bulbs.
Although, if both lights are doing the same thing I think that would eliminate the sockets as a problem. I would think that a socket problem would affect only one socket, not both.
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Thanks for all the suggestions! So I've already realigned my NSS as stated above and I'm getting current when I run an external load to the bulb sockets. Maybe the NSS is just bad? It may be cheaper just to run a physical switch mounted in the cab from the battery to the reverse lights 
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Ford Parts Specialist
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From: Simi Valley, CA
C7TZ-7A247-A .. NSS (Motorcraft SW-600) / Available from auto parts stores.
Applications: 1967/77 F100/350 all A/T's.
Applications: 1967/77 F100/350 all A/T's.
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300bigblock - you said you had a four speed manual? If so you need a different NSS switch than the one mike showed a picture of. Standard Motor products makes the LS-200 for the manual 4spd.
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I'll let you know if it works
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If the switch adjustment is okay, then I'd do like 74F2504by4 said and check the bulb sockets.
The contacts can be corroded or they could also be weak and not making good contact with the bulbs.
Although, if both lights are doing the same thing I think that would eliminate the sockets as a problem. I would think that a socket problem would affect only one socket, not both.
The contacts can be corroded or they could also be weak and not making good contact with the bulbs.
Although, if both lights are doing the same thing I think that would eliminate the sockets as a problem. I would think that a socket problem would affect only one socket, not both.
not in my case, both sockets were bad
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I didn't think it would have a nss
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SUCCESS!
Well I got the new NSS and plugged it in and manually moved the slider over the contacts AND............no worky
Before I took a blow torch to the old girl, I inhaled deeply, stepped back and took a much needed numerous day break 
I had some time this afternoon and took the dash apart again and started tracing wires. Lo and behold, I found where the reverse light wires come through the firewall and into the engine bay and into some sort of pigtail with a bladed wire jumper connecting both sides. Now I don't know if this was stock or simply someone's joke so I cut the sucker off and tied both ends together and tested.......GLORIOUS REVERSE LIGHTS IN REVERSE GEAR!!
I really appreciate everyone's help!!
PM me if you want a pic of the pigtail as I am not able to upload pics yet
Well I got the new NSS and plugged it in and manually moved the slider over the contacts AND............no worky
Before I took a blow torch to the old girl, I inhaled deeply, stepped back and took a much needed numerous day break I had some time this afternoon and took the dash apart again and started tracing wires. Lo and behold, I found where the reverse light wires come through the firewall and into the engine bay and into some sort of pigtail with a bladed wire jumper connecting both sides. Now I don't know if this was stock or simply someone's joke so I cut the sucker off and tied both ends together and tested.......GLORIOUS REVERSE LIGHTS IN REVERSE GEAR!!
I really appreciate everyone's help!!
PM me if you want a pic of the pigtail as I am not able to upload pics yet
Cargo Master
Joined: Oct 2010
Posts: 3,417
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SUCCESS!
Well I got the new NSS and plugged it in and manually moved the slider over the contacts AND............no worky Before I took a blow torch to the old girl, I inhaled deeply, stepped back and took a much needed numerous day break
I had some time this afternoon and took the dash apart again and started tracing wires. Lo and behold, I found where the reverse light wires come through the firewall and into the engine bay and into some sort of pigtail with a bladed wire jumper connecting both sides. Now I don't know if this was stock or simply someone's joke so I cut the sucker off and tied both ends together and tested.......GLORIOUS REVERSE LIGHTS IN REVERSE GEAR!!
I really appreciate everyone's help!!
PM me if you want a pic of the pigtail as I am not able to upload pics yet
Well I got the new NSS and plugged it in and manually moved the slider over the contacts AND............no worky
Before I took a blow torch to the old girl, I inhaled deeply, stepped back and took a much needed numerous day break I had some time this afternoon and took the dash apart again and started tracing wires. Lo and behold, I found where the reverse light wires come through the firewall and into the engine bay and into some sort of pigtail with a bladed wire jumper connecting both sides. Now I don't know if this was stock or simply someone's joke so I cut the sucker off and tied both ends together and tested.......GLORIOUS REVERSE LIGHTS IN REVERSE GEAR!!
I really appreciate everyone's help!!
PM me if you want a pic of the pigtail as I am not able to upload pics yet
