Roger Carter Posted September 18, 2017 Share Posted September 18, 2017 Hello All, Helping a friend get his '81 F-100 short narrow bed running and on the road. He purchased the truck as a rolling shell and has installed a 302 / C4 combination in the truck. The truck was originally an automatic truck, unsure of original engine or transmission. The truck also had factory cruise control, but that is not being reinstalled on this new engine. I have researched this site, and others, but have not found the information I am looking for. I am unable to find the wiring for the neutral safety switch in the truck's wiring. The wiring diagrams show the nss mounted on the transmission, in typical Ford fashion, but doesn't address the chassis wiring for it. I have a nss on the transmission but nothing to connect it to. Other Fords I have worked on had a tail coming out of an engine compartment wire loom that the nss and backlight switch would connect to. Typically this tail was in the middle of the firewall. This truck does not have this tail, and the loom appears to run into the cab near the heater, with no tail for the nss. I have read, on other sites, that the early 80's F-series do not show a nss, according to the Ford parts books. The parts books may not show a nss, but I am sure that would be an error in the book. I am aware the nss interrupts the "hot in start" wire between the ignition switch and solenoid and am able to wire the switch as such, but would like to locate the original wiring and tie into it. Any help to locate the original nss wiring / tail would be appreciated. Thanks in advance, Roger Carter Link to comment Share on other sites More sharing options...
PetesPonies Posted September 18, 2017 Share Posted September 18, 2017 Are you ABSOLUTELY sure it was an automatic trans from the factory? Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 18, 2017 Share Posted September 18, 2017 Roger - There does seem to be an omission in the 1981 EVTM, but the 1986 EVTM does show the NSS on Page 30 in the Start & Ignition section. Better yet, on Page 35 you can see where C128 is along the side of the driver's side frame. I'm pretty sure the 81's had an NSS as Dad's truck did/does and so did Rusty, and both are 81's. So I don't know why it doesn't show in the EVTM. The only thing to watch out for is that in '81 Ford used hash marks and dots on some of the wires, but in 1986 they replaced those with stripes. Link to comment Share on other sites More sharing options...
PetesPonies Posted September 19, 2017 Share Posted September 19, 2017 Are you ABSOLUTELY sure it was an automatic trans from the factory? If you look at the small wire on the solenoid, you should see the wire that goes to the NSS. Link to comment Share on other sites More sharing options...
Roger Carter Posted September 19, 2017 Author Share Posted September 19, 2017 Are you ABSOLUTELY sure it was an automatic trans from the factory? I am as sure as I can be that the truck was originally an automatic. The steering column appears factory and is an auto column. The the bell crank shift linkage appears to be in place and original to the truck. Thanks for the response. Link to comment Share on other sites More sharing options...
Roger Carter Posted September 19, 2017 Author Share Posted September 19, 2017 Roger - There does seem to be an omission in the 1981 EVTM, but the 1986 EVTM does show the NSS on Page 30 in the Start & Ignition section. Better yet, on Page 35 you can see where C128 is along the side of the driver's side frame. I'm pretty sure the 81's had an NSS as Dad's truck did/does and so did Rusty, and both are 81's. So I don't know why it doesn't show in the EVTM. The only thing to watch out for is that in '81 Ford used hash marks and dots on some of the wires, but in 1986 they replaced those with stripes. Thanks, Gary. I did see what you are talking about in the '86 EVTM and did notice the hash marks, dots, etc. on the wiring of the '81. I have connectors in the vicinity of the transmission inside the frame rail on the '81. I did a check previously and did not see the nss wiring though, I will check again and take a closer look. Thanks for the suggestions. Link to comment Share on other sites More sharing options...
Roger Carter Posted September 19, 2017 Author Share Posted September 19, 2017 If you look at the small wire on the solenoid, you should see the wire that goes to the NSS. Thanks for the input. I was aware the solenoid trigger wire (hot in Start) is the wire the nss interrupts. I just can't locate the ends of the wire that connect to the nss wiring. I was hoping to locate the factory wiring / connector since I really didn't want to start opening wire looms. If that is what it comes to, so be it. Just not my first choice. I appreciate the response. Link to comment Share on other sites More sharing options...
Gary Lewis Posted September 19, 2017 Share Posted September 19, 2017 Thanks, Gary. I did see what you are talking about in the '86 EVTM and did notice the hash marks, dots, etc. on the wiring of the '81. I have connectors in the vicinity of the transmission inside the frame rail on the '81. I did a check previously and did not see the nss wiring though, I will check again and take a closer look. Thanks for the suggestions. Don't miss Page 31 saying C128 is a gray connector near the dual brake warning switch and that it had 18 connections - which seems a lot more than I remember. Link to comment Share on other sites More sharing options...
PetesPonies Posted September 19, 2017 Share Posted September 19, 2017 Thanks for the input. I was aware the solenoid trigger wire (hot in Start) is the wire the nss interrupts. I just can't locate the ends of the wire that connect to the nss wiring. I was hoping to locate the factory wiring / connector since I really didn't want to start opening wire looms. If that is what it comes to, so be it. Just not my first choice. I appreciate the response. Wasn't expecting you to open harnesses, but to look for that color up by the firewall. If it was standard trans truck, that connector would be used to get power to the clutch pedal switch. But if it was an automatic, the connector has to be exposed. Look for that color near the brake master cylinder/firewall area. Link to comment Share on other sites More sharing options...
JimsRebel Posted September 19, 2017 Share Posted September 19, 2017 I am as sure as I can be that the truck was originally an automatic. The steering column appears factory and is an auto column. The the bell crank shift linkage appears to be in place and original to the truck. Thanks for the response. The wiring for the NSS located on the C6, exits the main harness near the base of the brake booster, on my 1986 F150. It travels down the left frame rail about a foot. You will see a 4 wire plug that connects to the very long pigtail of the NSS / backup light switch mounted left side of the C6. I am not sure if the C4 is in the same location. I am not completely convinced my truck will not start if I disconnect this connector. As my truck is an Auto, the column has a mechanical lockout to keep the key from rotating to the start position unless the gear selector is in Park or Neutral. This lockout means you don't need a NSS with an auto column. Jim Link to comment Share on other sites More sharing options...
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